THE 


GEOGRAPHY  OF  THE  HEAVENS, 


AND 


CLASS   BOOK  OF  ASTRONOMY, 


ACCOMPANIED   BT 


A   CELESTIAL  ATLAS. 


BY  ELIJAH  H.  BURRITT,  A.  M. 
-   *-         i*  >       - 


REVISED  AND  CORRECTED 

BY    O.    M.    MITCHEL,    A.M., 

DIRECTOR   OF  THE  CINCINNATI    OBSERVATORY. 


NEW    YORK: 
PUBLISHED   BY   HUNTINGTON   AND   SAVAGE, 

216  PEARL    STREET. 
CINCINNATI :— H.  W.  DERBY   &  CO. 

1849. 


Entered  according  to  Act  of  Congress/in  the  year  1848, 
BY  HUNTINGTON  &  SAVAGE, 

In  the  Clerk's  Office  of  the  District  Court  of  the  United  States  for  the  Southern 
District  of  New  York. 


o 


TABLE  OF  CONTENTS 


PAOB. 

Preface  to  the  first  edition,  .    .  7 

"     Mitchel's  edition,  ...  11 

Preliminary  chapter,  ....  17 

Magnitudes  of  stars,  ....  18 

Constellations,      ......  19 

Right  ascension  and  declination,  20 

Sidereal  time,  .......  22 

Table  for  finding  meridian  pas- 

sage of  objects  in  mean  time,  24 
Correction  for  mean  from  appa- 

rent time,   .......  26 

Definitions,  ........  26 

Greek  alphabet,  ......  34 

Andromeda,     .......  37 

Perseus  et  Caput  Medusse,  .    .  40 

Triangulum,    .  .    .....  44 

Cassiopeia,  ........  45 


Pisces,  ..........    51 

Aries,  ..........    55 

Cetus,  ..........    62 

Taurus,    .........    66 

Orion,  ..........    72 

Eridanus,     ........    79 

Auriga,    .........    81 

Gemini,   .....    .  .    .    .    85 

Cancer,    .........    90 

Canis  minor,   .......    93 

Monoceros,  .......        95 

Canis  major,   .......    96 

Leo  major,  ........  102 

Sextans,  ........  107 

Hydra,     .........  108 

Virgo,  ..........  113 

Corvus,    .........  118 


PAGE. 

Ursa  major,  ........  120 

Bootes,    .........  126 

Draco,  ..........  130 

Coma  Berenices,  ......  1  34 

Canes  Venatici,  ......  136 

Corona  Borealis,  ......  138 

Leo  minor,  ........  139 

The  Lynx,  ........  140 


Libra, 


141 


Scorpia,    .........  144 

Ursaminor,      .......  148 

.......  153 

......  155 

Sagittarius,  .    .    ......  157 

Scutum  Sobieski,'    .....  159 

Hercules,     ........  161 

Cygnus,  .........  165 


Lyra, 170 

AquUa  et   Antinous,  .    .    .    .174 

Delphinus, 177 

Vulpecula  et  Anser,  .    .    .    .179 
Serpentarius  vel  Ophiuchus,  .181 

Pegasus, 186 

Equulus  vel  Equi  Sectio,  .    .189 

Aquarius, 190 

Capricornus, 194 

Rising,  culminating,  and  setting 
of  the  visible   constellations 

in  each  month, 196 

Fixed  stars,  Parallax,  .    .    .    .201 
Distances  of  the  fixed  stars,  .  205 

Milky  Way, 206 

Clusters  and  Nebula,  ....  207 
Astral  system  and  central  sun,  209 

M298706  « 


vi 


TABLE  OF  CONTENTS. 


PAGE,  j 

Solar  system, 212 

The  Sun, 220 

Mercury 225 

Venus, .  229 

The  Earth 238 

The  Moon, 248 

Solar,  and  lunar  Eclipses,  .  .  253 
Eclipses  of  the  Sun,  ....  255 
Eclipses  of  the  Moon,  ....  258 

Mars, 261 

The  Asteroids,    ......  264 

Jupiter, 270 

Saturn, 275 

Uranus  or  Herschel,  .   .    .    .281 


PAGE. 

Neptune, 283 

Comets, 285 

Translation  of  the  sun  through 

space, 296 

Law  of  gravitation, 298 

Attractive  and  projectile  forces,  30 1 

Precession, 303 

Nutation,  Aberration,  ....  304 

Parallax, 305 

Refraction, 306 

Tides, 307 

The  Seasons, 312 

Astronomical  Instruments,  .    .321 
Questions,  tables,  &c.,    .    .    .  324 


PREFACE 

TO   THE   FIEST   EDITION. 

I  HAVE  long  felt  the  want  of  a  Class  Book,  which 
should  be  to  the  starry  heavens,  what  Geography  is 
to  the  earth ;  a  work  that  should  exhibit,  by  means 
of  appropriate  delineations,  the  scenery  of  the 
heavens,  the  various  constellations  arranged  in 
their  order,  point  out  and  classify  the  principal 
stars,  according  to  their  magnitudes  and  places, 
and  be  accompanied  at  the  same  time,  with  such 
familiar  exercises  and  illustrations,  adapted  to 
recitation,  as  should  bring  it  within  the  pale 
of  popular  instruction,  and  the  scope  of  juvenile 
understandings. 

Such  a  work  I  have  attempted  to  supply.  I  have 
endeavored  to  make  the  descriptions  of  the  stars  so 
familiar,  and  the  instructions  for  finding  them  so 
plain,  that  the  most  inexperienced  should  not  fail 
to  understand  them.  In  accomplishing  this,  I  have 
relied  but  little  upon  globes  and  maps,  or  books. 
I  very  early  discovered  that  it  was  an  easy  matter 
to  sit  down  by  a  celestial  globe,  and,  by  means  of 
an  approved  catalogue,  and  the  help  of  a  little 
graduated  slip  of  brass,  make  out,  in  detail,  a  minute 

(vii) 


viii  PREFACE  TO  THE  FIRST  EDITION. 

description  of  the  stars,  and  discourse  quite  fami- 
liarly of  their  position,  magnitude  and  arrangement, 
and  that  when  all  this  was  done,  I  had  indeed  given 
the  pupil  a  few  additional  facilities  for  finding  those 
stars  upon  the  artificial  globe,  but  which  left  him, 
after  all,  about  as  ignorant  of  their  apparent  situa- 
tion in  the  heavens,  as  before.  I  came,  at  length,  to 
the  conclusion,  that  any  description  of  the  stars,  to 
be  practically  useful,  must  be  made  from  a  careful 
observation  of  the  stars  themselves,  and  made  at 
the  time  of  observation. 

To  be  convinced  of  this,  let  any  person  sit  down 
to  a  celestial  globe  or  map,  and  from  this  alone, 
make  out  a  set  of  instructions  in  regard  to  some 
favorite  constellation,  and  then  desire  his  pupil  to 
trace  out  in  the  firmament,  by  means  of  it,  the  vari- 
ous stars  which  he  has  thus  described.  The  pupil 
will  find  it  little  better  than  a  fancy  sketch.  The 
bearings  and  distances,  and  especially,  the  compar- 
ative brightness,  and  relative  positions,  will  rarely 
be  exhibited  with  such  accuracy  that  the  young 
observer  will  be  inspired  with  much  confidence  in 
his  guide. 

I  have  demonstrated  to  myself,  at  least,  that  the 
most  judicious  instructions  to  put  on  paper  for  the 
guide  of  the  young  in  this  study  are  those  which  I 
have  used  most  successfully,  while  in  a  clear  eve- 
ning, without  any  chart  but  the  firmament  above,  I 
have  pointed  out,  with  my  finger,  to  a  group  of 
listeners,  the  various  stars  which  compose  this  and 
that  constellation. 


PREFACE   TO   THE   FIRST   EDITION.  IX 

In  this  way,  the  teacher  will  describe  the  stars 
as  they  actually  appear  to  the  pupil  —  taking  ad- 
vantage of  those  obvious  and  more  striking  features 
that  serve  to  identify  and  to  distinguish  them  from 
all  others.  Now,  if  these  verbal  instructions  be 
committed  to  writing,  and  placed  in  the  hands  of 
any  other  pupil,  they  will  answer  nearly  the  same 
end.  This  is  the  method  which  I  have  pursued  in 
this  work.  The  descriptive  part  of  it,  at  least,  was 
not  composed  by  the  light  of  the  sun,  principally, 
nor  of  a  lamp,  but  by  the  light  of  the  stars  them- 
selves. Having  fixed  upon  the  most  conspicuous 
star,  or  group  of  stars,  in  each  constellation,  as  it 
passed  the  meridian,  and  with  a  pencil  carefully 
noted  all  the  identifying  circumstances  of  position, 
bearing,  brightness,  number  and  distance  —  their 
geometrical  allocation,  if  any,  and  such  other  de- 
scriptive, features  as  seemed  most  worthy  of  notice, 
I  then  returned  to  my  room  to  transcribe  and  classify 
these  memoranda  in  their  proper  order ;  repeating 
the  same  observations  at  different  hours  the  same 
evening,  and  on  other  evenings  at  various  periods, 
for  a  succession  of  years ;  always  adding  such  emen- 
dations as  subsequent  observations  matured.  To 
satisfy  myself  of  the  applicability  of  these  descrip- 
tions, I  have  'given  detached  portions  of  them  to 
different  pupils,  and  sent  them  out  to  find  the  stars  ; 
and  I  have  generally  had  the  gratification  of  hearing 
them  report,  that  "  every  thing  was  just  as  I  had 
described  it."  If  a  pupil  found  any  difficulty  in 
recognizing  a  star,  I  re-examined  the  description 


X  PREFACE  TO  THE  FIRST   EDITION. 

to  see  if  it  could  be  made  better,  and  when  I  found 
it  susceptible  of  improvement,  it  was  made  on  the 
spot.  It  is  not  pretended,  however,  that  there  is 
not  yet  much  room  for  improvement ;  for  whoever 
undertakes  to  delineate  or  describe  every  visible 
star  in  the  heavens,  assumes  a  task,  in  the  ac- 
complishment of  which  he  may  well  claim  some 
indulgence. 


PREFACE 

TO   MITCHEL'S   EDITION. 

THE  extraordinary  discoveries  which  have  mark- 
ed the  History  of  Astronomy,  during  the  last  few 
years,  demand  corresponding  changes  in  the  books 
designed  for  the  instruction  of  those  who  seek  a 
knowledge  of  this  science.  Feeling  confident  that 
nothing  can  be  more  important,  than  the  furnishing 
of  our  schools  with  valuable  elementary  works  in 
science,  I  have  been  induced  to  undertake  the 
revision  and  the  re- writing  of  a  large  part  of  the 
well  known  school  book,  The  Geography  of  the 
Heavens.  In  consequence  of  the  rapid  advance  in 
Astronomy,  and  the  important  change,  which  has 
recently  commenced  in  our  country,  in  the  mode 
of  prosecuting  its  study,  this  revision  has  become  ab- 
solutely necessary.  When  this  work  first  appeared 
there  were  very  few  telescopes  in  the  United 
States,  and  of  these  a  very  small  proportion  were 
employed  in  the  schools  and  academies,  as  means 
of  instruction.  Hence,  at  that  time,  any  descrip- 
tion of  the  telescopic  objects,  found  within  the 


Xll  PREFACE   TO  MITCHEL'S   EDITION. 

limits  of  the  several  constellations,  would  have 
been  almost  useless.  Within  the  last  six  years  a 
new  era  in  Astronomical  science  has  dawned  on 
our  country.  A  zeal  and  ardor  has  been  aroused 
in  its  behalf,  which,  at  one  time,  was  regarded  as 
quite  impossible,  in  consequence  of  the  peculiar 
nature  of  our  government  and  institutions.  The 
reproach  cast  upon  us  by  Europeans,  for  our  utter 
neglect  of  science,  if  ever  just,  is  no  longer  so. 
Only  a  few  years  have  passed,  since  the  first  effort 
was  made  to  arouse  the  American  people  to  the 
importance  of  the  cultivation  of  Astronomical 
science,  and  we  now  are  able  to  point  to  no  less 
than  three  first  class  observatories,  all  erected 
within  the  last  five  years,  at  points  widely  dis- 
tant from  each  other.  The  example  thus  set  in 
the  West  and  the  East,  has  prompted  to  active 
effort  in  many  parts  of  our  country,  and,  at  this 
time,  there  is  scarcely  a  school  or  college  of  any 
rank,  at  which  it  has  not  been  resolved  to  attempt 
the  founding  of  an  Astronomical  Observatory,  of 
greater  or  less  magnitude.  To  meet  these  rapid 
changes  in  the  mode  of  conveying  the  truths  of 
Astronomy,  and  to  present,  in  simple  and  intelligible 
form,  the  results  of  the  recent  important  discoveries r 
will  be  the  main  objects  of  attention  in  the  revision 
of  this  work. 

A  large  part  of  the  Mythological  notices  will  be 


PREFACE  TO  MITCHEL'S  EDITION.  Xlll 

omitted,  as  less  important  than  the  description  of 
telescopic  objects  found  in  the  various  constella- 
tions. These  objects,  consisting  of  nebulae,  clusters, 
double,  triple,  multiple  and  binary  stars,  rich  fields 
and  vacant  spots,  will  be  noticed,  and  described, 
their  places  given,  and  drawings  of  the  more  im- 
portant objects,  with  a  note  of  the  diameter  of  the 
object  glass  which  will  show  them,  and  render  their 
observation  possible. 

Among  the  new  topics  treated,  we  may  notice 
the  following  as  some  of  the  more  important. 

The  subject  of  the  binary  and  double  stars,  their 
distances  and  periods  of  revolution,  has  engaged 
the  attention  and  talent  of  many  of  the  best  As- 
tronomers of  the  world,  for  the  last  twenty  years. 
These  revolving  suns  will  be  found  to  fill- their 
appropriate  places  in  the  revised  work.  The  en- 
larging of  the  limits  of  the  solar  system,  by  the 
discovery  of  a  planet  exterior  to  Uranus,  the  extra- 
ordinary means  of  its  discovery,  its  subsequent 
history,  and  the  elements  of  its  orbit,  constitute  a 
topic  of  deep  interest ;  add  to  this  the  discovery  of 
five  new  asteroids,  within  the  last  two  years,  and 
the  perfection  of  the  tables  of  all  the  old  planets, 
and  we  find  most  important  advances  in  our  knowl- 
edge of  the  solar  system. 

In  the  structure  of  the  Sidereal  Heavens,  and  our 

knowledge  of  the  distribution  of  the  stars  in  space, 
B 


Xiv  PREFACE  TO  MITCHEL'S   EDITION. 

little  had  been  done  after  the  death  of  Sir  W. 
Herschel,  until  within  the  last  few  years.  The  dis- 
covery of  the  actual  distance  of  a  fixed  star,  by 
Bessel,  gave  a  new  impulse  to  the  investigation  of 
these  sublime  subjects.  This  triumph  of  Bessel 
was  speedily  followed  by  many  others,  of  a  like 
kind.  M.  Argelander  demonstrates  the  motion  of 
the  sun  and  solar  system  in  space,  and  fixes  the 
point  towards  which  it  is  moving  ;  M.  Otho  Striive 
determines  its  annual  angular  motion  as  seen  from 
the  fixed  stars  of  the  first  magnitude ;  and,  finally, 
M.  Peters,  of  Russia,  fixes  the  distance  of  the  stars 
of  the  second  magnitude,  from  the  mean  parallax 
of  some  thirty  stars,  deduced  from  observation. 
With  these  data,  and  the  preceding  investigations 
of  Sir  W.  Herschel,  M.  Striive,  of  Pulkova,  Russia, 
commences  a  discussion  of  the  distribution  of  the 
stars  in  space ;  the  populousness  of  the  Milky  Way 
and  the  heavens,  generally, in  stars;  determines  the 
relative  distances  of  the  spheres  of  the  fixed  stars 
of  the  different  magnitudes ;  and,  finally,  they-  abso- 
lute distances,  and  the  actual  velocity  of  the  sun 
and  solar  system  through  space.  If  we  add  to 
these  topics  the  discoveries  by  Lord  Rosse's  great 
reflector,  the  changes  in  the  views  hitherto  enter- 
tained on  the  subject  of  La  Place's  nebular  hypo- 
thesis, and  Madler's  theory  of  the  great  central 
sun,  we  find  that  the  last  few  years  have  been  the 


PREFACE  TO  MITCHEL'S  EDITION.  XV 

most  wonderful,  and  the  most  fruitful,  in  the  whole 
history  of  Astronomy  since  the  time  of  Newton. 

The  necessity  of  a  new  edition  of  the  Geography 
of  the  Heavens  need  not  be  urged,  after  what  has 
been  said.  To  meet  the  demands,  a  new  set  of  star 
charts  have  been  prepared  expressly  for  this  work, 
and  the  text  will  be  found  to  conform  to  these 
charts. 

MOUNT  ADAMS,  May  1st,  1848. 


THE  REVISED 


GEOGRAPHY  OF  THE  HEAVENS. 


PRELIMINAEY  CHAPTER. 

THE  phenomena  of  the  heavens  have  excited  the 
curiosity,  and  fixed  the  attention,  of  mankind,  in  all 
ages  of  the  world.  The  beautiful  clustering  of  the 
bright  stars,  the  moving  planets,  the  extraordinary 
changes  of  the  moon,  the  phenomena  of  the  day 
and  night,  were  themes  for  study  at  a  period  so 
remote,  that  neither  history  nor  tradition  reach  far 
enough  back  in  the  past,  to  tell  us  when  or  by 
whom,  these  researches  were  commenced,  or  prose- 
cuted. From  the  earliest  ages,  down  to  the  present 
time,  the  science  of  astronomy  has  presented  prob- 
lems, taxing  the  highest  powers  of  the  human  in- 
tellect, and  requiring  for  their  solution  the  most 
profound  reasoning,  the  most  accurate  observation, 
the  most  powerful  instruments,  and  an  ardor,  perse- 
verance and  devotion,  which  have  signalized  human 
effort  in  no  other  department  of  scientific  research. 
"  The  heavens  declare  the  glory  of  God,"  and  the 
successful  examination  of  these  same  heavens,  has 
most  perfectly  demonstrated  that  other  great  truth, 
that  man  has  been  made  "  but  a  little  lower  than  the 
angels."  By  the  effort  of  his  genius,  he  has  risen 
to  a  knowledge  of  the  structure  and  laws  of  the 
universe,  he  has  vindicated  the  wisdom  of  God,  in 
the  beautiful  adjustments  of  the  moving  planets, 
and  the  harmonious  revolutions  of  a  multitude  of 
worlds,  linked  together  by  a  mysterious  bond.  He 
B2  (17) 


18         GEOGRAPHY  OF  THE  HEAVENS. 

has  extended  the  dominion  of  law  to  the  remote 
stars,  and  has  computed  the  periods  of  these  far 
distant  orbs.  But  these  sublime  results  have  not 
been  obtained  by  any  single  individual,  or  by  any 
one  nation.  The  great  problem  of  the  universe 
has  been  given  to  the  human  race,  and  its  solution 
has  been  the  progressive  work  of  all  nations,  in  all 
ages,  for  the  last  six  or  seven  thousand  years.  At 
the  end  of  this  vast  period,  we  gather  the  fruits  of 
all  preceding  effort,  and  condense  into  narrow 
limits  that  knowledge,  to  gain  which,  has  required 
the  highest  intellectual  activity  of  the  best  minds 
which  have  adorned  the  earth. 

In  looking  out,  of  a  clear  night,  on  the  starry 
heavens,  we  find  a  multitude  of  brilliant  objects, 
scattered  over  the  sky,  without  any  law  or  order  in 
their  distribution.  We  readily  remark  a  great  dif- 
ference in  the  brilliancy  of  the  stars,  and  our 
attention  is  soon  fixed  upon  certain  groups  of 
brighter  objects,  whose  configurations,  or  relative 
positions,  enable  us  to  find  them,  readily,  when 
they  are  in  the  visible  heavens.  The  diversity  in 
brightness  has  occasioned  the  classification  of  the 
stars,  in  order  of  their  brilliancy.  The  brightest 
occupy  the  first  class,  and  are  called  stars  of  the  first 
magnitude.  Of  these  there  are  only  a  few.  From 
the  brightest  stars  down  to  those  just  visible  to  the 
naked  eye,  the  scale  has  been  so  divided  that  it 
comprehends  six  magnitudes,  the  number  of  stars  in 
each  class  increasing  as  the  brightness  of  the  class 
decreases.  We  have  six  magnitudes  visible  to  the 
naked  eye,  and  then  the  telescopic  stars  carry  the 
series  down  to  the  sixteenth  magnitude,  and  even 
still  lower.  In  the  description  of  any  star,  then,  we 
must  always  give  its  magnitude,  as  one  means  of 
fixing  its  identity.  But  as  there  are  many  stars  in 
each  class,  the  magnitude,  alone,  would  riot  serve 
to  point  out  a  particular  star.  In  the  early  ages 
1 ' , 


PRELIMINARY  CHAPTER.  19 

of  astronomy,  the  heavens  were  divided  into  certain 
subdivisions,  or  groups  of  stars,  called  constellations; 
and  the  figure  of  some  animal,  or  other  object,  was 
assigned,  whose  outline  would  embrace  all  the  stars 
in  a  given  constellation.  These  subdivisions  have 
been  retained  in  modern  times,  and  although  at- 
tended with  many  inconveniences,  they  are  too 
firmly  fixed,  and  too  intimately  woven,  in  all  works 
on  astronomy,  ever  to  be  changed. 

There  is  no  resemblance  between  the  configura- 
tion of  the  stars,  and  the  object,  whose  name  is 
assigned  to  the  group ;  yet  when  the  limits  of  the 
constellation,  as  fixed  by  the  outline  of  the  object 
whose  name  it  bears,  becomes  accurately  known 
and  laid  down  on  maps,  these  subdivisions,  or 
constellations  of  stars,  greatly  assist  in  obtaining  a 
knowledge  of  the  heavens.  We  may  even  identify 
a  star,  by  knowing  it  is  the  brightest  of  a  given 
constellation.  To  render  it  possible  to  designate 
the  stars  of  each  constellation,  they  have  been 
named  after  the  letters  of  the  Greek  alphabet,  until 
these  are  exhausted,  calling  the  brightest  star  after 
the  first  letter,  and  so  on  down.  In  case  the  num- 
ber of  letters  is  insufficient  to  give  names  to  all  the 
visible  stars  in  a  constellation,  the  Roman  alphabet 
is  called  into  use,  and  after  this  is  exhausted,  the 
Arabic  characters,  1, 2,  3,  &c.,  are  employed.  Thus 
we  call  the  brightest  star  in  the  constellation  of  the 
Swan,  a  Cygni,  or  Alpha  of  the  Swan;  the  next 
brightest  in  the  same  constellation  is  called  3  Cygni, 
or  Beta  of  the  Swan  ;  Cygnus  being  the  Latin  for 
Swan,  and  Cygni,  meaning  of  tlie  Swan.  The  same 
is  true  of  the  other  constellations,  the  Latin  names 
being  always  retained  in  the  designation  of  the 
stars. 

If  the  constellations  contained  a  very  few  stars, 
and  those  of  marked  difference  of  magnitude,  this 
mode  of  designating  them  might  be  sufficient  for 


20         GEOGRAPHY  OF  THE  HEAVENS. 

their  identification  and  description.  But  in  con- 
sequence of  the  multitude  of  stars,  and  the  difficulty 
of  distinguishing  them  from  each  other  by  their 
magnitudes,  it  has  become  necessary  to  fix  their 
positions  in  the  heavens,  as  the  places  on  the 
earth's  surface  are  fixed  by  their  longitude  and 
latitude.  The  corresponding  terms  applied  to 
heavenly  bodies,  are  right  ascension  and  declination, 
which  terms  we  proceed  to  define. 

To  us  the  sun  appears  to  move  among  the  fixed 
stars,  and  in  the  course  of  one  year  to  return  again  to 
the  point  of  departure.  If  his  track  could  be  mark- 
ed by  leaving  behind  him  a  bright  line  of  fire,  this 
line  would  be  found  to  be  a  circle  traced  out  among 
the  fixed  stars,  and  this  track  of  the  sun  is  called 
the  ecliptic. 

There  are  two  points  in  this  track  of  especial 
interest,  from  the  fact  that  on  the  days  when  the 
sun  occupies  them,  the  length  of  the  day  and  night  is 
exactly  the  same,  each  being  twelve  hours.  These 
points,  on  the  ecliptic  or  sun's  track,  are  called  the 
equinoctial  points.  The  one  through  which  the  sun 
passes  in  the  spring,  is  called  the  vernal  equinox,  that 
occupied  by  the  sun  in  autumn  is  called  the  autumnal 
equinox. 

Each  day  and  night  the  sun,  and  other  heavenly 
bodies,  appear  to  describe  circles  in  the  heavens, 
called  diurnal  circles.  They  are  all  parallel  to 
each  other.  That  diurnal  circle  described  by  the 
sun,  at  either  equinox,  is  called  the  celestial  equator, 
or  the  equinoctial.  If  the  equinoctial  could  be  marked 
by  a  line  of  fire  in  the  heavens,  it  would  be  found 
to  cut  the  sun's  track,  or  the  ecliptic,  in  two  opposite 
points,  which  we  have  already  called  the  equinoctial 
points.  To  fix  the  place  of  a  star,  or  other  heavenly 
body,  it  is  referred  to  the  equinoctial,  or  celestial  equa- 
tor. A  star  on  the  north  side  of  the  equinoctial  is 
in  northern  declination,  and  one  on  the  south  side  of 


PRELIMINARY   CHAPTER.  21 

the  same  circle  is  in  southern  declination.  To  meas- 
ure the  distance  of  any  object  in  the  heavens,  north 
or  south  of  the  equator,  an  imaginary  circle  is  drawn 
through  the  object  perpendicular  to  the  equator,  and 
the  distance  measured  on  the  circle  thus  drawn  from 
the  object  to  the  equator  is  called  its  declination. 
Knowing  the  declination  of  a  star,  north  or  south 
of  the  equator,  does  not  suffice  to  fix  its  place  in 
the  heavens.  It  only  locates  it  on  the  circumfer- 
ence of  a  small  circle  parallel  to  the  equator,  and 
distant  from  it  by  an  amount  equal  to  the  known 
declination  of  the  object.  To  fix  the  exact  point 
of  the  object  on  this  small  circle,  it  is  only  neces- 
sary to  know  how  far  the  circle,  drawn  through  the 
object  and  perpendicular  to  the  equator,  cuts  the 
equator  from  the  vernal  equinox.  This  distance 
measured  on  the  equator,  from  the  vernal  equinox 
round  eastward,  is  called  the  right  ascension.  Any 
circle  drawn  through  a  heavenly  body,  and  perpen- 
dicular to  the  equator,  is  called  a  meridian.  That 
meridian  which  passes  through  equinoctial  points, 
is  called  the  prime  meridian,  or  the  equinoctial  co- 
lure.  Any  star,  or  heavenly  body,  situated  on  the 
prime  meridian,  has  no  right  ascension,  or  its  right 
ascension  is  equal  to  zero.  In  case  the  equator  be 
divided  into  twenty-four  equal  parts,  and  meridians 
be  drawn  through  the  points  of  division,  these 
meridians  are  called  hour  circles.  A  heavenly  body 
situated  on  the  first  hour  circle,  east  of  the  vernal 
equinox,  has  one  hour  of  right  ascension  ;  if  it  be  on 
the  second  hour  circle,  east,  it  will  have  two  hours 
of  right  ascension,  and  so  round,  through  the  twenty- 
four  hours  of  right  ascension  to  the  vernal  equinox 
again. 

That  point  in  the  heavens,  directly  above  us,  in 
which  a  perpendicular  to  the  surface  of  still  water, 
carried  upward,  would  pierce  the  celestial  sphere,  is 
called  the  zenith.  If  the  same  perpendicular  be 


22        GEOGRAPHY  OF  THE  HEAVENS. 

conceived  to  pass  downward  and  pierce  the  lower 
hemisphere,  the  point  of  piercing  is  called  the  nadir. 
The  circle  perpendicular  to  the  equator,  and  passing 
through  the  zenith  of  any  place,  is  called  the 
meridian  of  that  place.  All  points  on  the  earth's 
surface  in  the  same  longitude,  will  have  the  same 
meridian. 

The  instant  when  the  vernal  equinox  reaches  the 
meridian  of  any  place  on  the  earth's  surface,  is  the 
beginning  of  the  sidereal  dayy  which  terminates  when 
the  vernal  equinox  shall  have  passed  entirely  round 
and  returned  to  the  meridian  again.  A  clock,  or 
watch,  so  regulated  as  to  mark  0  hours  at  the  in- 
stant when  the  vernal  equinox  is  on  the  meridian 
of  a  given  place,  and  to  mark  the  hours  from  0  to 
twenty-four  hours,  is  called  a  sidereal  clock,  and 
keeps  sidereal  time.  It  will  be  found  that  the  right 
ascension  (marked  R.  A.)  of  each  object  is  given  in 
this  work.  In  case  the  right  ascension  of  a  star  is 
3  h.  12  m.  10  s.,  it  tells  us  that  it  will  reach  the 
meridian  3  h.  12  m.  10  s.  after  the  vernal  equinox 
has  passed  it.  If  the  time,  as  shown  by  a  sidereal 
clock,  is  less  than  the  R.  A.  of  a  star,  then  the  star 
has  not  yet  reached  the  meridian  ;  on  the  contrary, 
should  th^time  indicated  by  the  sidereal  clock  be 
greater  tharHhe  R.  A.  of  any  object,  then  the  object 
has  already  passed  the  meridian,  and  is  west  of  it 
by  an  amount  equal  to  the  difference  between  the 
sidereal  time  and  the  R.  A.  To  render  this  clear, 
take  the  following  examples. 

The  R.  A.  of  a  star  is  4  h.  26  m.  10  s.,  the  sidereal 
time  is  3  h.  15  m.  25  s.  Is  the  star  east  or  west  of 
the  meridian  ?  It  is  east  of  the  meridian,  and  to 
find  the  amount  by  which  it  is  east, 

From  the  R.  A.  =  4  26'  10 

Subtract  3  15  25    the  time. 

Diff.  =  1  10  45 


PRELIMINARY  CHAPTER.  23 

In  case  the  sidereal  time  is  5  h.  12  m.  20  s.,  then 
the  star  has  already  passed  the  meridian,  and  is 
west  by  an  amount  found  as  follows  : 


H.    M.      S. 

From  the  time       =5  12  20 
Subtract  the  A.  R.  =4  26  10 


DifE  =  0  46  10 

Or  the  star  is  0  h.  46  m.  10  s.  west  of  the  meridian. 
Any  one  possessing  a  sidereal  time  piece,  whether 
clock  or  chronometer,  will  find  no  difficulty  in  fixing 
the  place  of  a  heavenly  body,  as  to  its  angular  dis- 
tance east  or  west  of  the  meridian,  at  any  hour  in 
the  twenty-four.  The  declination  of  the  object, 
shows  its  distance  north  or  south  of  the  equator, 
and  combining  the  two,  the  A.  R.  and  the  Declina- 
tion, we  have  the  exact  position  of  the  object  in 
question.  It  frequently  happens  that  persons  are 
not  provided  with  sidereal  time  pieces,  but  may 
possess  very  good  solar  clocks,  chronometers  or 
watches.  Mean  solar  time  is  reckoned  from  the 
instant,  that  the  center  of  the  mean  sun  (or  one 
moving  with  the  mean  motion  of  the  true  sun),  is 
on  the  meridian.  It  differs  from  sidereal  time,  by 
3  m.  56.5554  s.  in  each  twenty-four  hours,  or  a 
sidereal  clock  gains  that  amount  daily  on  a  mean 
solar  clock.  Hence  we  perceive  that  mean  solar 
and  sidereal  time  seldom,  if  ever,  agree.  When 
any  heavenly  body  is  on  the  meridian  of  a  given 
place,  a  well  regulated  sidereal  clock  will  show  the 
time  exactly  equal  to  the  right  ascension  of  the  body. 
No  such  relation  exists  between  mean  solar  time  and 
the  right  ascension. 

To  find  the  instant  that  an  object,  whose  right 
ascension  is  given,  reaches  the  meridian  in  mean 
solar  time,  or  that  shown  by  ordinary  clocks  and 
watches,  the  following  table  has  been  computed. 


24 


GEOGRAPHY   OF  THE  HEAVENS. 


U's  Jan. 

Feb.)  Mir. 

April.     May. 

June.     July. 

Aug. 

Sep.. 

Oct. 

Nov 

Dec. 

h.  m. 

h.  m. 

h.  m. 

h.  m.  '  b.  m. 

b.  in.     h.  m. 

h    m. 

h.  m 

b.  m. 

h  m 

h.  m 

15  14 

3  01 

1  1223  18;21  27 

19  24  17  20 

15  15 

1  .1  19 

11  31  9  35 

7  31 

25  09 

2  57 

1  08J23  15  21  23 

19  20  17  16 

15   ll 

13  15 

11  27 

9  31 

727 

35  04 

2  53 

1  04i23  11  21   19 

19  16  17  12  15  07 

13  12 

11  24 

9  27 

7  22 

45  00 

2  49 

1   01  23  0721  16 

19  12  17  08 

15  04 

13  08 

11  20  9  23 

7  18 

54  56 

2  45 

0  57 

23  04  21  12 

19  08  17  04 

15  00 

13  0,3 

11  17 

9  19 

7  14 

64  51 

2  41 

0  53 

23  00  21  08 

19  04  16  59 

14  56 

13  01 

11  13 

9  15 

7  09 

74  47 

2  37 

0  49J22  56  21  04 

19  00  16  55 

14  52 

12  57  11  09 

9  11 

7  05 

8j4  42 

2  33 

0  46  22  53  21  00 

18  56  16  51 

14  48  12  54J11  06 

9  07 

7  01 

9  14  38 

2  29 

0  42 

22  49  20  56 

18  51  16  47 

14  44  12  50 

11  0-2 

9  03 

6  56 

10  4  34 

2  25 

0  38 

22  45(20  52 

18  47  16  43 

14  41 

12  47 

10  58 

8  59 

6  52 

11  !4  29 

a  21 

0  35 

22  42'20  48 

18  43  16  39 

14  3712  43 

10  55 

8  55 

6  47 

12  "4  25 

2  17 

0  31 

22  38:20  44 

18  39  16  35 

14  33  12  39 

10  51 

8  51 

6  4  J 

134  21 

2  13 

0  27 

22  34,  20  41 

18  35  16  31 

14  29:12  36 

10  47 

8  47 

6  39 

144  162  09 

0  24 

22  31  20  37 

18  31  16  27 

14  2«|l2  32 

10  43 

8  43 

6  34 

154  12 

2  05 

0  2(» 

22  27  20  33 

18  27  16  23 

14  22 

12  29 

10  40 

839 

6  30 

164  OS 

2  01 

0  16 

22  23120  29 

18  2-2  Ifi  19 

14  18 

12  25 

10  3f> 

8  35 

6  25 

174  04 

1  57 

0  13 

22  20|20  25 

18  18  16  15 

14  14  12  21  10  32 

8  30 

6  21 

18  3  59 

1  54 

0  09 

22  16J20  21 

18  111     11 

14  11  12  18 

10  28 

8  26 

6  16 

19  3  55il  50 

0  06 

22  1220  17 

18  10  16  07 

14  07,12  14 

10  25 

8  22 

6  12 

203  51 

1  46 

0  02 

22  08  20  13 

18  0616  01 

14  03 

12  11 

10  21 

8  18 

«  08 

21  '3  47 

1  42 

23  58 

22  05  20  09 

18  02  15  59 

3  59 

12  07 

10  17 

8  14 

6  03 

22|3  42 

1  38  23  55 

•J2  01  20  05 

17  57  15  55 

13  56  12  03 

10  13 

8  09 

5  59 

23  3  38  1  34  23  51 

21  57  20  01 

17  53  15  51 

3  52  12  00 

10  10 

8  05 

5  54 

243  341  31123  47 

21  5319  57 

17  49  15  47 

13  4811  56 

10  06 

8  Oi 

5  50 

25  3  30 

1  27 

23  44 

21  50  19  53 

17  45  15  4J 

13  4511  53 

10  02 

7  57 

5  45 

26326 

1  23 

23  40 

21  46  19  49 

17  41  15  39 

13  41 

11  49 

9  58 

7  53 

5  41 

273  21  1   1923  36 

21  42il9  45 

17  37  15  35 

13  37  1  1  45 

9  54 

7  48 

5  36 

28  3  17  1  16  23  33 

21  38  19  41 

17  32  15  31  13  34  11  421  9  50 

7  44 

5  32 

29  3  13  1   14  23  29 

21  35  19  37 

17  28  15  27 

13  30  1  1  38 

9  47  7  40 

5  28 

303  09!....  -J3  25 

21  31:19  32 

17  24  15  23 

13  26  11  35 

9  43,7  a' 

3  23 

31  13  05  ....  23  22 

19  28  1  15  19 

13  23  9  39|..-- 

'  19 

A  few  examples  will  suffice  to  explain  the  use  of 
this  table. 

Given  the  A.  R.  of  Sirius  =  6  h.  38  m.  07  s. — 
required  the  apparent  time  of  its  meridian  passage, 
on  January  llth. 

RULE. —  To  the  number  placed  opposite  the  date,  add 
the  A.  R.  of  the  star,  as  found  in  this  work. 


H.    M.     S. 

Thus :  A.  R.  of  Sirius  =  6  38  07 
Tabular  No.          4  29  00 


11  07  08 


PRELIMINARY  CHAPTER.  25 

Or  Sirius  passes  the  meridian  at  11  h.  07  m.  08  s. 
apparent  time. 

EXAMPLE. — Required  the   apparent  time    of  the 
meridian  passage  of  Vega,  on  May  30th. 

A.  R.  of  Vega  =  18  31  34 
Tabular  No.  =  19  32  00 


Sum  =  38  03  34 
*  Subtract  24  hours  24  00  00 

Meridian  passage  14  03  34  apparent  time. 

It  will  be  noticed  that  the  foregoing  computations 
have  been  made  for  apparent  time.  This  is  slightly 
different  from  the  time  shown  by  clocks  and  watches, 
called  mean  time.  Apparent  noon  is  the  exact  in- 
stant when  the  true  sun's  center  is  on  the  meridian. 
In  consequence  of  the  apparent  irregular  motion 
of  the  sun,  there  is  a  variable  difference  between 
apparent  or  true  time,  or  that  shown  by  the  sun,  and 
mean  time,  or  that  shown  by  the  clock. 

Since  we  rely  for  our  time  on  the  clock,  we  here 
present  a  table  which  will  exhibit  the  mean  days  in 
the  year,  on  which  a  clock  or  watch,  regulated  to 
mean  time,  will  be  an  even  number  of  minutes  faster 
or  slower  than  the  sun. 

From  this  table  it  is  easy  to  reduce  the  apparent 
time  of  any  meridian  passage,  found;  by  the  pre- 
ceding table,  to  mean  or  clock  time.  To  be  rigidly 
accurate,  the  correction  should  be  taken  from  the 
nautical  almanac,  or  other  accurate  ephemeris,  but 
for  ordinary  gazing  these  tables  are  quite  sufficient. 

*  In  case  the  sum  produced  by  adding  to  the  tabular  number  opposite 
the  given  date  the  A.  R.  of  the  star,  or  other  heavenly  body,  be  greater 
than  twenty-four  hours,  from  the  sum  subtract  twenty-four  hours,  and  the 
remainder  will  be  the  apparent  time  of  meridian  passage. 

c 


26 


GEOGRAPHY  OF  THE  HEAVENS. 


Days. 

Cor. 
ID 
min. 

Day,. 

Cor. 
in 

linn. 

Days. 

Cor. 
min. 

Days. 

Cor. 
in 
min. 

Days. 

Cor. 
in 
min. 

Days. 

JSJ 

Jan.    2 

4  F 

Mar  12 

10  F 

May    1 

3   b 

Aug.  16  4  F 

Sept.  27 

9    S 

i)ec.     j,9    S 

"    4 

5  F 

"    15 

9  F 

"     15 

4   S 

'•    20 

3  F 

'•    30 

10    S 

•'8   S 

1  «    tf 

6  F 

"    19 

8  F 

"    28 

3  S 

«    242  F 

Oct.    3 

11   S 

107   S 

"  11 

8  F 

"    22 

7  F 

June  5 

2  S 

"    28 

1  F 

"      612   S 

126   S 

*k    14 

9  F 

"    25 

6  F 

"    11 

1   S 

Sept.  10 

"     1013   S 

145   S 

"    16 

10  F 

'•    28 

5  F 

il    15 

0 

'•      3 

1   S 

"     14 

14   S 

164   S 

«    19 

11  F  April  1 

4  F 

"    19 

1  F 

t;      6 

2  S     '•    19 

15   S 

183  S 

"    23 

12  Fj     "      4 

3  F 

«    24 

2  F 

«      9 

3  S     ««    2716  S 

2012   S 

«    27 

1.3  F      "      7 

2  F 

«    29 

3  F 

'     12 

4   S  Nov.  16115  S 

22 

1    S 

Feb.    3 

14  F     «    11 

1  F 

Tuly    4 

4  F 

'•     155   S      "    2014   S 

24 

0 

«    28 

13  F      "    15 

0 

«    10 

5  F 

';    18 

6   S     "    2413  S 

26 

1  F 

Mar.   4 

12  F      "    19 

1   S 

"    21 

6  F 

"    21  7   S      "    27  12   S 

28 

2  F 

«'      8 

11  F      "    24 

2"   S 

A  us:.  10 

5  F 

"    24 

8  SDec.    310  S 

30 

3  Fj 

Now,  returning  to  the  examples  already  given 
of  the  meridian  passages  of  Sirius  and  Vega ;  the 
first  of  these  stars  was  found  to  culminate  or  pass 
the  meridian  at  11  h.  07  m.  08s.  apparent  time,  on  the 
lltb  Jan.  By  the  last  table,  on  the  llth  of  Janu- 
ary, the  clock  is  8  m.  faster  than  the  sun.  Hence 
the  culmination  by  the  clock  will  take  place  at 
10  h.  59m.  08s. 

Again,  Vega  was  found  to  culminate  at  14  h.  03  m. 
34s.,  on  the  30th  May,  apparent  time.  By  the 
preceding  table,  on  the  28th  of  May  the  clock  was 
3m.  slower  than  the  sun,  and  gaining  one  minute 
in  7  days,  or  about  9s.  per  day.  On  the  30th  the 
clock  will  be  slow,  about  2  m.  42  s. ;  and  hence 
Vega  will  culminate,  by  the  clock,  14  h.  03  m.  34  s. 
+  2m.  42s.  =  14  h.  06m.  16s. 

These  approximations  are  sufficiently  accurate 
for  ordinary  purposes. 

The  first  table  will  not  be  in  error  more  than  1  m. 
for  twenty  years,  when  the  stars  will  culminate 
about  one  minute  later  than  shown  by  the  table. 

From  all  the  foregoing  considerations  we  deduce 
the  following  definitions : 

The  magnitude  of  a  star  is  its  brightness  compared 
with  any  star  assumed  as  a  standard. 

A  star  of  the  1st  magnitude  is  of  the  highest  order 
of  brightness. 


PRELIMINARY  CHAPTER.  27 

All  stars  below,  the  6th  magnitude  are  only  rendered 
visible  by  telescopic  aid. 

A  constellation,  is  a  group  of  stars  falling  within 
the  limits  of  the  outline  of  any  animal  or  object 
whose  name  it  bears,  and  whose  figure  is  conceived 
to  be  drawn  in  the  heavens,  and  is  actually  drawn 
on  globes  and  maps  of  the  heavens. 

The  ecliptic,  is  the  path  which  the  sun  appears  to 
describe  in  a  year  among  the  fixed  stars. 

The  equator  or  the  equinoctial,  is  a  great  circle  cut 
from  the  heavens  by  producing  the  plane  of  the 
earth's  equator  to  meet  the  celestial  sphere.  The 
equinoxes  are  the  points  in  which  the  celestial  equa- 
tor and  the  ecliptic  cut  each  other. 

Diurnal  circles,  are  those  circles  which  the  heaven- 
ly bodies  appear  to  describe  every  twenty-four 
hours.  They  are  all  parallel  to  the  equator. 

Meridians,  are  great  circles  perpendicular  to  the 
celestial  equator,  and  meeting  in  the  points  called 
the  north  and  south  poles  of  the  heavens. 

Hour  circles,  are  meridians,  cutting  the  equator  so 
as  to  divide  it  into  twenty-four  equal  parts  ;  the 
first  point  of  division  being  at  the  vernal  equinox. 

The  zenith,  is  the  point  in  which  a  perpendicular 
to  the  surface  of  still  water,  pierces  the  celestial 
sphere  above. 

The  nadir ,is  where  the  same  perpendicular  pierces 
the  celestial  sphere  below. 

The  meridian  of  any  place,  is  the  great  circle,  per- 
pendicular to  the  celestial  equator,  and  passing 
through  the  zenith  of  the  place.  The  right  ascension 
of  a  heavenly  body,  is  its  distance  east  of  the  vernal 
equinox,  -reckoned  on  the  celestial  equator. 

The  declination  of  a  heavenly  body,  is  its  distance 
north  or  south  of  the  equator,  measured  on  a  meri- 
dian passing  through  the  heavenly  body. 

The  declination  is  expressed  in  degrees,  minutes 
and  seconds,  of  a  great  circle,  and  is  expressed  by 


28  GEOGRAPHY  OF  THE  HEAVENS. 

these  symbols,  °  '  ".  Thus  we  write  12  degrees, 
17  minutes,  10  seconds  :  12°  17'  10". 

A  sidereal  day ',  is  the  interval  from  the  instant  the 
vernal  equinox  is  on  the  meridian  of  a  given  place, 
till  it  again  reaches  the  same  meridian. 

A  true  solar  day,  is  the  interval  from  the  instant 
the  center  of  the  true  sun  is  on  the  meridian  of  a 
given  place, till  it  again  reaches  the  same  meridian. 

A  mean  solar  day,  is  the  interval  from  the  instant 
that  the  center  of  an  imaginary  sun  (moving  with 
the  mean  daily  motion  of  the  true  sun)  is  on  the 
meridian  of  any  given  place,  till  it  reaches  again 
the  meridian  of  the  same  place. 

The  equinoctial  colure,  is  a  meridian  passing 
through  the  equinoctial  points. 

Parallels  of  declination,  are  small  circles,  north  or 
south  of  the  equator,  and  parallel  to  it. 

The  rational  horizon,  is  a  plane  passing  through 
the  center  of  the  earth,  and  perpendicular  to  the 
radius  drawn  to  any  place  on  the  earth's  surface. 
It  divides  the  heavens  into  two  hemispheres,  the 
upper  being  the  visible,  the  lower  the  invisible  hemi- 
sphere. 

Any  heavenly  body  is  in  the  act  of  rising,  when 
it  passes  from  below  up  through  the  plane  of  the 
rational  horizon.  It  is  setting,  when  in  the  act  of 
passing  below  this  same  plane. 

The  sensible  horizon,  is  the  circle  limiting  our 
view,  or  where  the  earth  and  sky  appear  to  meet. 

Vertical  circles,  pass  through  the  zenith,  and  per- 
pendicular to  the  horizon. 

The  prime  vertical,  is  the  great  circle,  which  cuts 
the  horizon  in  the  east  and  west  points. 

Before  proceeding  to  an  exploration  of  the 
heavens,  it  will  be  necessary  to  acquire  some  know- 
ledge of  the  classes  of  objects,  the  individuals  of 
which  will  be  hereafter  described.  The  most  ca- 
sual observer  cannot  fail,  on  the  first  examinaiion 


PRELIMINARY   CHAPTER.  29 

of  the  heavens,  to  notice  an  irregular  zone,  of  une- 
qual brightness,  called  the  Milky  Way,  which  is  seen 
to  sweep  entirely  round  the  celestial  sphere.  This 
bright  zone  is  found  to  consist  of  millions  of  stars, 
scattered  with  rich,  but  irregular  profusion,  through- 
out its  entire  extent.  Nearly  all  its  stars  are  below 
the  sixth  magnitude,  and  are,  of  course,  invisible  to 
the  naked  eye.  But  the  smallest  telescopic  aid 
reveals  multitudes  of  stars ;  and  as  the  power  of 
the  telescope  is  increased,  the  number  of  stars 
brought  to  view  increases  in  a  like  proportion. 
Although,  according  to  the  investigations  of  modern 
science  (to  be  more  fully  examined  hereafter),  we 
may  not  fix  absolute  bounds  and  limits  to  the  mil- 
lions of  stars  composing  the  Milky  Way,  yet  if  we 
confine  our  examinations  to  the  richer  or  denser 
portions,  we  are  able  to  assign  a  figure  within 
whose  limits  the  Milky  Way  will  be  confined. 
Were  it  possible  to  enclose  all  the  stars  composing 
the  Milky  Way  in  some  opaque  envelope  which 
would  shut  them  out  from  all  space  beyond,  within 
this  envelope  and  not  very  far  from  its  center,  our 
own  sun,  itself  a  fixed  star,  would  be  found-  Having 
thus  enclosed  the  stars  of  the  Milky  Way  in  imagi- 
nation, it  is  found  that  the  space  on  the  outside  of 
this  envelope  is  not  void  space.  Very  far  beyond 
this  limit,  the  telescope  has  revealed  objects  of 
greater  or  less  brightness,  which,  when  examined 
with  powerful  instruments,  are  found  to  consist  of 
millions  of  minute  points,  grouped  together,  and 
assuming  all  possible  forms,  among  which  the  glo- 
bular manifestly  predominates.  These  are  called 
clusters  of  stars,  and  are  in  many  instances  so  large, 
as  to  occupy  as  much,  if  not  more  space  than  that 
taken  up  by  the  Milky  Way,  and  containing,  inall  pro- 
bability, as  many  stars.  These  magnificent  dusters 
are  so  remote,  that  the  telescope  may  often  grasp,  at 
one  view, their  vast  extent,  and  innumerable  millions 
c2 


30         GEOGRAPHY  OF*  THE  HEAVENS. 

of  stars.  Other  bright  objects  are  seen  beyond  the 
limits  of  the  stars  composing  the  Milky  Way,  which 
assume  all  possible  shapes,  and  which,  in  many 
respects,  resemble  the  clusters  ;  with  this  difference, 
that  no  telescopic  power  has  ever  revealed  any 
stars  within  their  limits.  These  are  called  nebulce, 
or  faint  luminous  clouds.  Among  the  nebulae,  some 
present  characteristics  which  indicate  the  fact,  that 
in  case  they  could  be  examined  with  greater  tele- 
scopic power,  they  would  be  found  to  be  composed 
of  stars  too  remote  to  be  seen  separately,  but  whose 
combined  light  reaches  us  from  their  vast  distances, 
and  shows  them  as  faint  luminous  clouds.  There 
are  others  which  exhibit  no  such  characteristics, 
and  which  many  astronomers  believe  consist  of 
luminous  matter,  resembling  that  composing  the 
tails  of  comets.  These  are  called  irresolvable  nebula. 
In  this  class,  the  most  remarkable  are  the  planetary 
nebula,  so  called  from  the  fact  that  they  present 
disks,  very  like  those  of  the  planets,  with  a  lumi- 
nous surface  of  uniform  brightness.  They  resemble 
the  very  distant  planets  of  our  system,  and  are,  in 
some  instances,  only  a  little  less  bright. 

Among  the  stars  we  reckon  the  following  classes, 
viz. : 

Single  stars,  double  stars,  multiple  stars,  binary  stars, 
periodical  or  variable  stars,  new  stars,  and  nebulous 
stars. 

Single  stars,  are  those  which,  to  the  naked  eye, 
and  under  telescopic  examination,  are  found  to 
consist  of  one  individual  star. 

Double  stars,  are  those  which,  to  the  naked  eye, 
appear  single,  but  which,  under  telescopic  exami- 
nation, are  found  to  consist  of  two  stars.  Some- 
times the  component  stars  are  equal,  at  other  times 
they  are  very  unequal,  the  relative  magnitude  and 
distance  being  different  in  every  set. 

Multiple  stars,  are  such  as  are  seen  single,  by  the 


PRELIMINARY  CHAPTER.  31 

naked  eye,  but  which  the  telescope  finds  composed 
of  three  or  more  components. 

Binary  stars,  are  double  stars,  in  which  the  com- 
ponents have  been  found  to  be  united  in  such  a 
way  that  they  revolve  around  each  other.  These 
are  suns  revolving  about  suns,  and  not  a  planet 
about  a  sun. 

Variable  stars,  are  those  which  are  found  to  under- 
go certain  fluctuations  in  brightness.  Sometimes 
they  are  found  to  lose  their  light,  and  actually  to 
become  invisible.  Then  they  regain  their  brilliancy, 
by  slow  degrees,  and  reach  their  original  brightness. 
In  some  individuals  these  changes  are  accomplished 
in  a  certain  fixed  period ;  in  other  cases  the  fluctu- 
ations of  light  are  not  governed  by  any  known  law. 

New  stars,  are  those  which  have  suddenly  blazed 
'forth  in  some  region  of  the  heavens  previously 
blank  or  vacant.  They  generally  die  away  and 
disappear  in  the  course  of  one  or  two  years. 

Nebulous  stars,  are  such  as  are  surrounded  by  a 
faint  halo,  or  luminous  haze  of  nebulous  matter. 

It  will  be  readily  remarked  that  all  these  objects, 
except  the  single  stars,  are  telescopic,  and  are  invi- 
sible to  the  naked  eye. 

The  region  in  the  heavens  about  four  degrees 
on  each  side  of  the  ecliptic,  or  sun's  path,  is  called 
the  zodiac,  and  is  remarkable  as  the  region  in  which 
the  sun,  moon,  and  large  planets  perform  their 
revolutions  among  the  fixed  stars.  The  constella- 
tions, into  which  the  stars  in  the  region  of  the  zo- 
diac were  divided,  are  doubtless  among  the  most 
ancient  in  the  heavens.  In  consequence  of  the 
apparent  annual  motion  of  the  sun  among  the  con- 
stellations of  the  zodiac,  the  stars  of  these  constel- 
lations will  be  successively  lost  in  the  superior 
brilliancy  of  the  sun,  and  will  become  invisible 
while  in  the  immediate  vicinity  of  the  sun.  This 
remark  is  true  of  all  the  constellations  beyond  the 


32        GEOGRAPHY  OF  THE  HEAVENS. 

limits  of  the  zodiac,  and  near  enough  to  the  sun's 
track  to  be  above  the  horizon  with  the  sun,  and  to 
be  extinguished  by  his  light.  As  we  approach  the 
north  pole  of  the  heavens,  we  find  certain  groups 
of  stars  or  constellations  which  never  sink  below 
the  horizon,  and  are  consequently  visible  at  all 
seasons  of  the  year.  Others,  more  remote  from  the 
north  pole,  sink  below  the  horizon,  and  disappear 
for  only  a  short  time. 

As  the  stars  about  the  south  pole  of  the  heavens 
never  rise  above  the  horizon  of  any  place  in  our 
northern  latitudes,  they  are  never  visible  to  us  ;  and 
to  be  seen  to  advantage,  the  spectator  must  travel 
to  southern  latitudes. 

The  Atlas  which  accompanies  this  work,  contains 
detailed  maps  of  all  the  principal  constellations, 
involving  the  stars  down  to  the  sixth  magnitude, 
inclusive,  the  principal  clusters,  nebulae,  double 
stars,  &c.  The  constellation  exhibited  on  any  map, 
is,  in  general,  surrounded  by  its  bounding  constella- 
tions, so  as  to  show  their  relative  positions.  This 
necessarily  occasions  the  repetition  of  certain  con- 
stellations on  several  maps.  But  the  map  intended 
for  use,  in  the  study  of  each  constellation,  is  referred 
to  in  the  text  describing  the  constellation. 

As  each  judicious  instructor  will  select  his  own 
method  of  teaching  the  constellations  to  his  classes, 
it  has  been  thought  best  not  to  arrange  this  work 
with  reference  to  one  invariable  plan,  which  must 
be  followed  to  render  it  useful.  It  is,  in  general, 
better  to  study  a  constellation,  when  it  occupies  a 
position  in  the  heavens  far  enough  above  the  hori- 
zon to  render  all  its  stars  visible.  This  can  only 
occur  at  a  certain  season  of  the  year  ;  and  as  classes 
will  commence  the  study  of  astronomy  at  any  con- 
venient time,  this  work  is  so  arranged  that  the 
teacher  can  commence  at  any  constellation  which 
may  be  favorably  situated  for  examination  at  the 


PRELIMINARY   CHAPTER.  33 

time  when  his  class  enters  upon  the  study  of  the 
heavens. 

In  teaching  the  constellations,  it  is  certainly  best 
to  commence  with  some  one  in  which  the  principal 
stars  are  large  and  brilliant,  and  thus  easily  recog- 
nized ;  such  as  the  stars  in  Ursa  Major,  or  in  Lyra, 
or  in  Orion,  or  in  Taurus.  Having  adopted  any 
point  of  departure  easily  recognized,  it  will  not  be 
difficult  to  refer  the  surrounding  constellations  to 
this  point,  and  gradually  to  extend  the  examina- 
tion until  it  embraces  the  whole  visible  heavens. 

The  maps  present,  as  nearly  as  may  be,  pictures 
of  the  heavens,  as  seen  with  the  naked  eye.  A 
faint  outline  of  the  figure  whose  name  the  constel- 
lation bears,  is  found  on  the  map  ;  not  so  prominent 
as  to  become  the  striking  object,  but  sufficiently 
distinct  for  all  useful  purposes  of  reference.  These 
outlines  must  be  retained,  as  the  stars  are  most 
readily  described,  and  their  places  found,  by  their 
positions  in  the  constellation.  Thus  we  speak  of 
the  bright  star  Albireo,  in  the  Ull  of  the  Swan ;  Al- 
debaran,  in  the  eye  of  the  Bull,  &c. ;  and  by  the  lo- 
cality thus  given,  the  eye  seizes  the  object  on  the 
map  at  a  glance. 

The  parallels  of  declination  and  the  hour  circles 
have  not  been  drawn  on  the  map,  to  prevent  con- 
fusion ;  but  the  degrees  of  declination  are  marked 
on  the  right  and  left  of  the  map,  and  the  hours  of 
Right  Ascension  at  the  top  and  bottom.  Hence  it 
is  easy  to  determine,  from  the  maps,  the  A.  R.  and 
Dec.  of  any  object. 

The  double  stars  are  at  once  recognized,  on  the 
maps,  by  being  double  and  round,  while  all  other 
stars  are  stellated  or  star-shaped.  The  nebulae 
and  clusters  are  readily  distinguished  as  small  faint 
objects,  on  the  maps. 

We  commence  with  the  constellations  upon  and 
to  the  east  of  the  prime  meridian,  and  shall  trace 


34         GEOGRAPHY  OF  THE  HEAVENS. 

them  in  the  order  in  which  they  appear  to  reach  the 
meridian,  going  eastward  round  the  celestial  sphere. 
As  Greek  letters  so  frequently  occur  in  catalogues 
and  maps  of  the  stars,  and  on  the  celestial  globes, 
the  Greek  alphabet  is  here  introduced  for  the  use 
of  those  who  are  unacquainted  with  it.  The  capi- 
tals are  seldom  used  for  designating  the  stars,  but 
are  here  given  for  the  sake  of  regularity. 


A 
B 
r 
A 
E 
z 
H 
0 
I 
K 
A 
M 
N 

s 

O 
n 
P 
S 

T 
T 
* 
X 

•*• 
ii 

To  find  in  what  part  of  the  heavens  to  look  for  a 
constellation,  at  any  season  of  the  year  and  hour 
of  the  night,  examine  the  map,  and  note  the  mean 
right  ascension  of  the  constellation  in  question. 
Then  find  by  the  rule  (page  14)  the  meridian  pas- 


THE     GREEK 

ALPHABET. 

a 

Alpha 

a 

ft 

Beta 

b 

y 

Gamma 

g 

s 

Delta 

d 

e 

Epsilon 

e  short 

f 

Zeta 

z 

n 

Eta 

e  long 

Theta 

th 

* 

Iota 

i 

x 

Kappa 

k 

X 

Lambda 

1 

/* 

Mu 

m 

V 

Nu 

n 

| 

Xi 

x 

0 

O  micron 

o  short 

n 

Pi 

P 

p 

Rho 

r 

f 

Sigma 

8 

f 

Tau 

t 

v 

Upsilon 

U 

t 

Phi 

ph 

2 

Chi 

ch 

4* 

Psi 

ps 

to 

Omega 

o  long 

PRELIMINARY  CHAPTER.  35 

sage  of  the  mean  right  ascension  of  the  constella- 
tion on  the  given  day.  In  case  the  time  at  which 
you  seek  the  constellation  is  later  than  the  time  of 
meridian  passage,  then  the  center  of  the  constella- 
tion has  passed  the  meridian;  on  the  contrary, 
should  it  be  earlier,  the  constellation  is  east  of  the 
meridian,  and  its  angular  distance  from  the  meri- 
dian will  be  expressed  by  the  difference  between 
the  time  of  meridian  passage  of  the  center  point  of 
the  constellation  and  the  time  of  examination. 

EXAMPLE. — Where  must  we  look  for  the  constel- 
lation Andromeda,  at  ten  o'clock,  p.  M.,  on  the  12th 
of  October  ? 

From  Map  No.  1,  the  right  ascension  of  the 
middle  point  of  this  constellation  is  about  one  hour. 

H.  M.    8. 

A.  R.  of  the  middle  point,  =     1  00  00 
Tab.  No., =  10  51  00 

Sum  =  11  51  00 
Time,  10  o'clock,  subt., 10  00  00 

1  51  00 

The  center  of  the  constellation  is,  therefore, 
Ih.  51m.  east  of  the  meridian ;  and  as  the  mean 
declination,  shown  by  the  map,  is  about  40°  north, 
its  place  may  be  readily  found  in  the  heavens. 

It  will  be  well  for  the  student  to  fix  in  the  heavens 
some  standard  of  measure,  in  degrees  and  in  hours. 
Each  hour  of  right  ascension  contains  fifteen  de- 
grees of  arc.  The  distance  from  the  zenith  to  the 
horizon  is  90°,  or  one  quarter  of  the  whole  circum- 
ference. If  this  distance  be  divided  by  the  eye  into 
six  equal  parts,  each  of  these  parts  will  be  15°.  It 
should  be  remembered  that  hours  of  A.  R.  are 
always  measured  on  the  equator,  and  the  hour 
circles  are  just  15°  apart  at  the  equator,  but  con- 
verge to  a  point  at  either  pole.  Hence  the  space 


36         GEOGRAPHY  OF  THE  HEAVENS. 

intercepted  on  the  parallels  of  declination  by  two 
adjacent  hour  circles,  grow  smaller  the  farther  the 
parallel  is  from  the  equator,  either  north  or  south. 

In  the  notices  of  the  double  and  binary  stars,  the 
distance  of  the  components,  and  the  angle  formed 
by  a  line  drawn  from  the  center  of  the  larger  com- 
ponent through  the  center  of  the  smaller  one,  with 
the  meridian,  counting  from  the  north  to  the  east 
round  the  circle,  are  given,  with  the  date  or  epoch 
at  which  the  given  distance  and  position  were  ob- 
served. It  is  by  means  of  measures  of  the  distances 
and  angles  of  position,  that  it  becomes  possible, 
after  many  years  of  observation,  to  compute  the 
curves  which  the  binary  stars  describe,  in  their 
orbitual  motion  around  their  common  center  of 
gravity. 

In  the  description  of  the  components,  the  largest 
star  is  called  --.----  A, 
The  next  in  size,  -  -  -  B; 

and  if  there  be  more  components  than  two,  as  is  the 
case  with  multiple  stars,  they  are  named  A,  B,  C, 
D.  &c.,  in  the  order  of  magnitude. 

In  many  instances  there  is  a  marked  difference 
in  the  color  of  the  components  of  double  and  mul- 
tiple stars.  Whenever  this  difference  is  readily 
recognized,  the  colois  are  given  in  the  description 
of  the  components. 


CONSTELLATION  OF  ANDROMEDA.  37 


CHAPTER  I. 

DIRECTIONS  FOR  TRACING  TFIE  CONSTELLATIONS  ON 
MAP   NO.  I. 

ANDROMEDA. 

PERSEUS  ET  CAPUT  MEDUSAE. 
TRIANGULUM.     THE  TRIANGLE. 
CASSIOPEIA. 

Favorably  situated  for  examination  in  November,  De- 
cember, and  January. 

ANDROMEDA. 

If  we  look  directly  over  head  at  10  o'clock,  on  the 
10th  of  November,  we  shall  see  the  constellation 
celebrated  in  fable,  by  the  name  of  ANDROMEDA.  It 
is  represented  on  the  map  by  the  figure  of  a  woman 
having  her  arms  extended,  and  chained  by  her 
wrists  to  a  rock.  It  is  bounded  N.  by  Cassiopeia, 
E.  by  Perseus  and  the  head  of  Medusa^  and  S.  by 
the  Triangle  and  the  Northern  Fish.  It  is  situated 
between  20°  and  50°  of  N.  declination.  Its  mean 
right  ascension  is  nearly  15°,  or  one  hour  E.  of  the 
equinoctial  colure. 

It  consists  of  66  visible  stars,  of  which  two  are 
of  the  2d  magnitude,  and  two  of  the  3d;  most  of 
the  rest  are  small. 

The  stars  directly  in  the  zenith  are  too  small  to 
be  seen  in  the  presence  of  the  moon,  but  the  bright 
star  Almaack,  marked  y,  of  the  3d  magnitude,  in 
the  left  knee,  may  be  seen  13°  due  E.,  and  Merach, 
marked  £,  of  the  2d  magnitude,  in  the  girdle,  7°  south 
of  the  zenith.  This  star  is  then  nearly  on  the  meridi- 
an, and  with  two  others  N.  W.  of  it,  form  the  girdle. 
D 


38         GEOGRAPHY  OF  THE  HEAVENS. 

The  three  stars  forming  the  girdle  are  of  the  2d, 
3d,  and  4th  magnitude,  situated  in  a  row,  3°  and  4° 
apart,  and  are  called  ,3,  i",  and  v. 

If  a  straight  line,  connecting  r  with  $  be  pro- 
duced southwesterly,  8°  farther,  it  will  reach  to  6,  a 
star  of  the  3d  magnitude,  in  the  left  breast.  This 
star  may  be  otherwise  known  by  its  forming  a  line. 
N.  and  8.,  with  two  smaller  ones  on  either  side  of 
it ;  or  by  its  constituting,  with  two  others,  a  very 
small  triangle,  S.  of  it. 

Nearly  in  a  line  with  r,  /3  and  5,  but  curving  a 
little  to  the  N.,  7°  farther,  is  a  lone  star  of  the  2d 
magnitude,  in  the  head,  called  Aipheratz,  or  a  An- 
dromeda. This  is  the  N.  E.  corner  of  the  great 
f<  Square  of  Pegasus,"  to  be  hereafter  described. 

It  will  be  well  to  have  the  position  of  Aipheratz 
well  fixed  in  the  mind,  because  it  is  but  one  minute 
W.  of  the  great  equinoctial  colure,  or  first  meridian 
of  the  heavens,  and  forms  nearly  a  right  line  with 
a,  in  the  wing  of  Pegasus,  14°  South  of  it,  and 
with  3,  in  Cassiopeia,  30°  N.  of  it.  If  a  line,  con- 
necting these  three  stars,  be  produced,  it  will 
terminate  in  the  pole.  These  three  guides,  in  con- 
nection with  the  North  Polar  Star,  point  out  to  as- 
tronomers the  position  of  that  great  circle  in  the 
heavens  from  whiph  the  right  ascension  of  all  the 
heavenly  bodies  is  measured. 

Bode  has  registered  226  stars  in  Andromeda. 

TELESCOPIC    OBJECTS. 

A  DOUBLE  STAR.— A.  R.  =  0  h.  1  m.  43  s.  Dec. -f-  25°  01'  2",  on 
the  crown  of  Andromeda's  head,  in  a  coarse  cluster.  A  10,  B  11  mag., 
both  reported  pale  blue.  According  to  Sir  William  Herschel,  this  star  is 
surrounded  by  extensive  nebulosity,  exceedingly  faint  and  diffused.  No 
outline  has  yet  been  given  by  even  the  most  powerful  instruments. 

Pos.  120°  0'.     Dist.  28".00.     Epoch  1836.81. 

22  ANDROMEDA.— A.  R.  =  0  h.  2  m.  2  s.  Dec.  -f-  45°  IQf  9",  a  fine 
double  star,  in  the  Milky  Way,  between  the  left  hand  of  Andromeda  and 
the  head  of  Cassiopeia.  A  5,  B  8  magnitude. 


CONSTELLATION  OF   ANDROMEDA.  39 

Stationary.     Pos.  85°  5'.     Dist.  4". 7.     Epoch  1835. 

v  ANDHOMEDJE A.  R.=  0  h.  28  m.  21  s.    Dec.  =  32°  50'.    A  coarse 

double  star,  on  the  left  breast  of  Andromeda.     A  4£,  B  9  magnitude. 
Stationary.     Pos.  173°  9'.     Dist.  35". 6.     Epoch  1832.90. 

THE  GREAT  NEBULA  IN  ANDROMEDA. — A.  R.  =  0  h.  34  m.  5  s. 
I)ec-  —  _|_  40°  23'  6".  Known  as  far  back  as  905  A.  D.,  and  of  course 
discovered  by  the  naked  eye.  Besides  being  the  oldest  nebula  on  record, 
it  is  the  only  one  fairly  visible  without  the  aid  of  the  telescope  ;  yet  to  see 
it  requires  a  keen  eye,  and  a  pure  atmosphere.  It  was  rediscovered  by 
Simon  Marius,  with  the  unaided  eye,  and  first  examined  by  him  with  the 
telescope,  on  the  15th  Dec.,  1612.  Owing  to  the  variety  in  the  power 
of  the  telescopes  used  by  different  observers,  in  the  examination  of  this 
object,  it  has  received  great  diversity  of  description  ;  some  call  it  round, 
others  oval.  Cassini  thought  it  nearly  triangular. 

Sir  William  Herschel  considered  this  the  nearest  of  all  the  great  nebu- 
Ise ;  on  what  ground  I  know  not,  unless  it  be  its  apparent  magnitude. 
He  considers  its  distance  to  be  about  two  thousand  times  the  distance  of 
Sirius!  and  if  Sirius  be  as  remote  as  61  Cygni,  then  would  the  light  of 
this  object  require  no  less.than  twenty  thousand  years,  at  twelve  million 
miles  per  minute  of  time,  to  reach  us.  Such  periods  and  distances  are 
not  more  overwhelming  than  the  magnitude  of  the  object  under  exam- 
ination. Great  as  the  above  distance  may  appear,  in  case  we  are  to  re- 
gard this  mi4y  light  as  an  aggregation  of  millions  of  distant  suns,  we  must 
sink  it  vastly  deeper  in  space,  to  reconcile  the  hypothesis  with  the  fact 
that  the  stars  which  compose  it  have  never  been  revealed  by  the  most 
powerful  instrument. 

There  is  a  small  attendant,  or  companion,  discovered  by  Le  .lentil  in 
Nov.,  1749,  which  has  been  partially  resolved  into  stars  by  Lord  Rosse's 
three  feet  Reflector. 

The  drawing  was  made  while  under  inspection  with  the  twelve  inch 
Refractor  of  the  Cincinnati  Observatory. 

36  ANDROMEDJE.— A.  R.  =  0  h.  46  m.  24  s.  Dec.  -f-  22°  45'  7". 
A  very  close  double  star,  in  the  right  elbow  of  Andromeda.  A  6,  B  7 
magnitude ;  both  of  a  golden  color.  The  measures  indicate  a  binary 
character. 

Pos.  307°  04'     Dist.  0".90      Epoch  1830.78     Herschel. 
320    47  0  .937  1836.90     Struve. 

322    9  1   .000  1843.12     Smyth. 

330    14  1   .050  1847.70     Mitchel. 

ju.  ANDROMEDA.— A.  R.  =  0  h.  47  m.  53  s.  Dec.  -}-  37°  37'  8".  A 
wide  double  star  in  the  girdle  of  Andromeda.  A  4,  B  16  magnitude. 

Pos.  110-  28'.     Dist.  49".  19.     Epoch  184267,  Challis. 

This  object  is  difficult,  in  consequence  of  the  minute  size  of  the 
companion. 

55  ANDROMEDA.— A. R.  =  1  h.  43  m.  42  s.  Dec.  =-j-  39°  56'  2". 
A  delicate  double  star  on  the  left  leg  of  Andromeda.  A  5£,  B  16 


40         GEOGRAPHY  OF  THE  HEAVENS. 

magnitude.  Discovered  by  Herschel,  and  marked  as  "  a  fine  specimen 
of  a  nebulous  star." 

Pos.  350°  0'.     Dist.  25". 0.     Epoch  1832.95. 

y  AXDROMED.E. — A.  R.  =  1  h.  54  m.  06  a.  Dec.  =-}-  41°  33'  6". 
A  magnificent  triple  star  on  the  left  knee  of  Andromeda.  A  3^,  B  and 
C  combined  make  a  star  of  5£  magnitude.  This  star  was  known  to  be 
double  as  far  back  as  1778.  The  star  was  examined  and  measured  as 
double  by  all  subsequent  observers  down  to  Struve,  who  in  1812,  with 
the  great  refractor  of  the  Pulkova  observatory,  first  divided  the  small  star 
into  two,  making  it  a  triple  set.  The  distance  between  the  close  green 
stars  cannot  exceed  0  '.4,  and  to  see  it  fairly  double  requires  a  most  power- 
ful instrument.  I  obtained  many  measures  of  this  object,  and  succeeded 
in  dividing  the  stars,  clearly,  showing  a  difference  in  the  magnitude  of  the 
components.  The  measures  of  angles  of  position,  agree  remarkably  well 
with  each  other,  and  give  the  pos.  1 10C  00'.  Dist.  0".40.  Epoch  1 846.fi. 

It  is  worthy  of  remark,  that  the  first  examinations  of  this  object,  made 
by  myself,  were  with  a  diminished  aperture.  These  were  unsuccessful, 
and  it  was  only  after  the  full  aperture  was  employed  that  the  stars  were 
clearly  divided.  This  division  requires  a  capital  atmosphere,  and  a 
smooth  clock  motion,  for  its  accomplishment.  * 

Pos.  A  to  B,  62°  9'.     Dist.  10".  6.     Epoch  1837.80. 

AT*  ELONGATED  NEBTTLA.— A.  R.  =  2  h,  12m.  35  s.     Dec.  =  -f- 

41°  36'  1".  On  the  right  foot,  a  little  above  a  line  drawn  from  $  Persei  to 
y  Andromedae,  at  about  two-thirds  the  distance  from  the  first  star.  It  very 
much  resembles  an  annulus  seen  very  obliquely.  It  was  discovered  by 
Miss  Caroline  Herschel,  in  August  1783,  with  a  very  ordinary  reflector, 
and  a  power  of  thirty  times.  The  dark  space  along  the  greater  axis,  was 
clearly  seen  by  Sir  William  Herschel,  and  he  regarded  the  object  as  an 
immense  ring  of  myriads  of  stars,  so  remote  that  their  individuality  was 
lost  under  his  greatest  space-penetrating  power. 


PERSEUS,    ET    CAPUT    MEDUSA. 

PERSEUS  is  represented  with  a  sword  in  his  right 
hand,  the  head  of  Medusa  in  his  left.  It  is  situa- 
ted directly  N.  of  the  Pleiades  and  the  Fly,  between 
Andromeda  on  the  W.  and  Auriga  on  the  E.  Its 
mean  declination  is  49°  N.  It  is  on  the  meridian 
the  24th  of  December.  It  contains,  including  the 
head  of  Medusa,  59  stars,  one  of  which  is  of  the  2d 
magnitude,  and  four  of  the  3d.  According  to  Eu- 
dosia,  it  contains,  including  the  head  of  Medusa,  67 
stars. 


CONSTELLATION  OF  PERSEUS.  41 


"  Perseus  next, 

Brandishes  high  in  heaven  his  sword  of  flame, 
And  holds  triumphant  the  dire  Gorgon's  head, 
Flashing  with  fiery  snakes  !  the  stars  he  counts 
Are  sixty-seven  ,•  and  two  of  these  he  boasts, 
Nobly  refulgent  in  the  second  rank — 
One  in  his  vest,  one  in  Medusa's  head." 

THE  HEAD  OF  MEDUSA  is  not  a  separate  constella- 
tion, but  forms  a  part  of  Perseus. 

It  is  represented  as  the  trunkless  head  of  a  fright- 
ful Gorgon,  crowned  with  coiling  snakes,  instead  of 
hair,  which  the  victor  Perseus  holds  in  his  hand. 

There  are,  in  all,  about  a  dozen  stars' in  the  Head 
of  Medusa  ;  two  of  the  4th  magnitude,  and  one, 
varying  alternately  from  the  2d  to  the  4th  magnitude. 
This  remarkable  star  is  called  Algol,  and  marked  /3. 
It  is  situated  12°  E.  of  y,  in  the  knee  of  Andromeda, 
and  may  be  known  by  means  of  three  stars  of  the  4th 
magnitude,  lying  a  few  degrees  S.  W.  of  it,  and 
forming  a  small  triangle. 

It  is  on  the  meridian  the  21st  of  December  ;  but 
as  it  continues  above  the  horizon  18  hours  out  of 
24,  it  may  be  seen  every  evening  from  September 
to  May.  It  varies  from  the  2d  to  the  4th  magni- 
tude in  about  3j  hours,  and  back  again  in  the  same 
time  ;  after  which  it  remains  steadily  brilliant  for 
2f  days,  when  the  same  changes  recur. 

The  periodical  variation  of  Algol  was  determin- 
ed in  1783,  by  John  Goodricke  of  York  (Eng.)  to  be 
2  days,  20  hours,  48  minutes,  and  56  seconds. 

Dr.  Herschel  attributes  the  variable  appearance 
of  Algol  to  spots  upon  its  surface,  and  thinks  it  has 
a  motion  on  its  axis  similar  to  that  of  the  sun.  He 
also  observes,  of  variable  stars  generally  : — "  The 
rotary  motion  of  stars  upon  their  axes  is  a  capital 
feature  in  their  resemblance  to  the  sun.  It  appears 
to  me  now,  that  we  cannot  refuse  to  admit  such  a 
motion,  and  that  indeed  it  may  be  as  evidently  prov- 
ed as  the  diurnal  motion  of  the  earth.  Dark  spots, 

D2 


42  GEOGRAPHY   OF  THE  HEAVENS. 

or  large  portions  of  the  surface  less  luminous  than 
the  rest,  turned  alternately  in  certain  directions 
either  towards,  or  from  us,  will  account  for  all  the 
phenomena  -of  periodical  changes  in  the  luster  of 
the  stars,  so  satisfactorily,  that  we  certainly  need 
not  look  out  for  any  other  cause." 

It  is  said  that  the  famous  astronomer  Lalande, 
who  died  at  Paris  in  1807,  was  wont  to  remain 
whole  nights,  in  his  old  age,  upon  the  Pont  Neuf]  to 
exhibit  to  the  curious  the  variations  in  the  brillian- 
cy of  the  star  Algol. 

Nine  degrees  E.  by  N.  from  Algol,  is  the  bright  star 
Algenib,  marked  a,  of  the  2d  magnitude,  in  the  side  of 
Perseus,  which  with  y  Andromeda,  makes  a  perfect 
right  angle  at  Algol,  with  the  open  part  towards  Cas- 
iopeia.  By  means  of  this  strikingly  perfect  figure, 
the  three  stars  last  mentioned  may  always  be  re- 
cognized without  the  possibility  of  mistaking  them. 
Algenib  may  otherwise  be  readily  distinguished  by 
its  being  the  brightest  and  middle  one  of  a  number 
of  stars  lying  four  and  five  degrees  apart,  in  a  large 
semicircular  form,  curving  towards  Ursa  Major. 

Algenib  comes  to  the  meridian  on  the  21st  De- 
cember, 15  minutes  after  Algol,  at  which  time  the 
latter  is  almost  directly  over  head.  When  these 
twro  stars  are  on  the  meridian,  that  beautiful  cluster, 
the  Pleiades,  is  about  half  an  hour  E.  of  it ;  and  in 
short,  the  most  brilliant  portion  of  the  starry  heav- 
ens is  then  visible  in  the  eastern  hemisphere.  The 
glories  of  the  scene  are  unspeakably  magnificent ; 
and  the  student  who  fixes  his  eye  upon  those  lofty 
mansions  of  being,  cannot  fail  to  covet  a  knowledge 
of  their  order  and  relations,  and  to  "  reverence  Him 
who  made  the  Seven  Stars  and  Orion." 

The  Milky-Way  around  Perseus  is  very  vivid, 
being  undoubtedly  a  rich  stratum  of  fixed  stars,  pre- 
senting the  most  wonderful  and  sublime  phenom- 
enon of  the  Creator's  power  and  greatness.  Koh- 


CONSTELLATION  OF  PERSEUS.  43 

ler,   the    astronomer,  observed  a  beautiful  nebula 
near  the  face  of  Perseus,  besides  eight  other  nebu- 
lous clusters  in  different  parts  of  the  constellation. 
Bode  has  registered  196  stars  in  this  constellation. 

TELESCOPIC    OBJECTS. 

76  M.  PERSEI.— A.  R.  =  1  h.  32  m.  16s.  Dec  =  -f  50°  46'  5",  an 
oval  white  nebula,  close  to  the  toe  of  Andromeda,  though  in  the  limits  of 
Perseus.  Discovered  by  Mechain.  Messier  pronounced  it  a  compressed 
cluster  ;  while  Herschel  thought  it  a  double  irresolvable  nebula.  With 
the  Northumberland  Equatorial,  Cambridge,  Eng.  it  has  a  spangled  ap- 
pearance. Prof.  Challis  says  "  the  resolution  is  very  doubtful." 

A  MAGNIFICENT  CLUSTER. — A.  R.  =  2  h.  07  m.  58  s.  Dec. 
-j-  56°  24'  4".  In  the  sword  handle  of  Perseus.  This  is  certainly  one 
of  the  most  brilliant  and  beautiful  objects  in  the  heavens ;  under  favor- 
able circumstances,  the  field  of  view  glows  and  sparkles  with  innumer- 
able diamonds,  on  a  ground  dark  and  rich  as  the  blackest  velvet. — In  the 
center,  five  stars  are  arranged  in  the  form  of  a  bow  strongly  bent,  while  a 
bright  8th  mag.  star  is  situated  precisely  at  the  point  where  the  thumb 
and  finger  would  hold  the  arrow.  This  cluster  is  considered  by  Sir  W. 
Herschel,  and  with  reason,  as  a  protuberant  portion  of  the  Milky- Way, 
or  vast  stratum  of  stars  of  which  our  own  sun  is  an  individual — With 
the  full  aperture  of  the  12  inch  Refractor,  all  haziness  disappears,  and  the 
heavens  beyond  are  completely  dark  and  pure,  showing  that  the  vision  has 
pierced  entirely  beyond  the  limits  of  space  occupied  by  these  stars,  and 
that  the  interval  between  them  and  the  nearest  group  beyond  is  so  great 
as  to  hide  them  absolutely  from  the  view.  No  drawing  can  give  any 
idea  of  the  splendor  of  this  object.  The  one  which  accompanies  this 
description  was  taken  with  care,  and  gives  a  correct  idea  of  position  and 
relative  magnitude,  but  not  of  the  sparkling  beauty  of  the  stars. 

Ax   ELONGATED    NEBULA. — A.   R.    =   2   h.    30   m.  25  s.     Dec, 

—  _|_  38°  2 1'  Near  the  head  of  Medusa.  Discovered  by  Herschel, 
1 786.  This  is  probably  one  of  those  stupendous  rings  of  stars  forming 
a  separate  universe,  like  our  own,  and  seen  under  great  obliquity. 

S.  PERSEI.— A.  R.  =2  h.  33m.  8s  Dec  =  48°  32' 9",  A  Tri- 
ple star  on  the  left  shoulder  of  Perseus.  A  4,  yellow  ;  B  1 3,  violet ; 
C.  11,  gray. — No  change  in  position  seems  to  have  occurred  since  first 
discovered  by  Herschel  in  1782.  Dist.  A  to  B  =  15" 

A  to  C  =  27" 

*  PERSEI.— A.  R.  =  2  h.  39  m.  04  s.  Dec.  =  55°  13'  5".  A  double 
or  rather  multiple  star  on  the  head  of  Perseus.  A  5,  orange ;  B  8  •$, 
blue.  There  are  many  stars  in  the  field.  The  principal  one  has  three 
small  stars  on  one  side,  and  one  on  the  other,  all  nearly  in  the  same 
straight  line,  and  forming  a  miniature  of  Jupiter  and  his  satellites. 


44  GEOGRAPHY  OF  THE  HEAVENS. 

No  change  in  position,  yet  detected. 

£  PERSEI,  Algol— A.  R.  —  2  h.  57  m.  46  s.  Dec.  =  _|_  40°  20' 
A  coarse  double  star  in  the  head  of  Medusa,  on  the  shield  of  Perseus. — 
A  2  to  4  mag.  B.  1 1.  This  is  the  most  wonderful  among  the  variable 
stars.  The  rapidity  and  regularity  of  its  changes,  the  great  amount  of 
change  in  brilliancy,  and  its  double  character,  mark  it  as  a  most  extra- 
ordinary object.-^It  diminishes  from  the  2d  to  the  4th  magnitude  in  about 
3^  hours,  retains  its  diminished  splendor  about  18  minutes,  and  in  3^  hours 
resumes  by  degrees  its  former  splendor. — Its  period  is  '2d.  20  h.  48  m.  56s. 

«  PERSEI.— A.  R.  ==  3  h.  47  m.  08  s.  Dec.  =  -|-  39°  32'  4",  a  fine 
double  star  near  the  left  leg  of  Perseus.  A  3g,  B  9.  Discovered  by 
Herschel. 

Pos.  =  8°32/         Dist.  =  8'.00         Ep.  1780.59     Herschel. 

A  COMPRESSED  GROUP. — A.  R.  =  3  h.  58  m.  11s.  Dec.  =  -|-  49° 
04'  in  the  left  knee  of  Perseus. — First  registered  by  Herschel  1 790. 


TRIANGULUM. 

The  Triangle  is  supposed  to  have  derived  its  name 
from  the  Egyptian  Delta.  Formerly  there  was  but 
one  Triangle  ;  a  second  was  added  by  Hevelius,  and 
is  retained  on  the  map. 

The  Triangles  are  situated  between  the  head  of 
Aries,  on  the  south,  and  the  knee  of  Andromeda,  on 
the  north.  They  contain  one  star  of  the  third,  and 
one  of  the  fourth  magnitude.  The  other  stars  are 
small. 

Ptolemy  reckoned,  in  this  constellation,  four  stars ; 
Hevelius,  nine  ;  Piazzi,  twenty-five;  and  Bode  has 
registered  thirty-three  stars.  Most  of  them  are  tele- 
scopic. 

TELESCOPIC   OBJECTS, 

A  LARGE  FAINT  NEBULA — A.  R.  =  1  h.  24  m.  51  s.  Dec.  -f-  29  ° 
51' 03";  between  the  head  of  the  Northern  Fish  and  the  Triangle. 
Discovered  by  Messier,  1764;  resolved  by  Herschel,  1783,  into  minute 
stars.  He  locates  this  object  in  the  334th  order  of  distances,  or  regards 
it  as  334  times  more  remote  than  stars  of  the  first  magnitude. 


CONSTELLATION   OF  CASSIOPEIA.  45 

i  TRIAXGULI.— A.  R.=l  h.  53  m.  38  s.  Dec  =  -f-  32°  30'  05".  A 
close  double  star  on  the  triangle.  A  5£,  B  15,  mag.  Discovered  by 
Strive. 

Pos.  110°  0'         Dist.  =5"         Epoch  1835.75     Smyth. 

/  TRIANGULI, — A.  R.  =  2  h.  3m.  06  s.  Dec.  =  -|-  29°  33'.  A 
close  double  star,  under  the  base  of  the  triangle.  A  5-£,  "  topaz  yellow," 
B  7,  "green."  Discovered  by  Herschel.  Recent  measures  indicate 
fixity  in  the  components. 

Pos.  77°  50'         Dist.  30".598         Epoch  1830.97     Struve. 

A  CLOSE  DOUBLE  STAR. — A.  R.  =  2  h.  19  m.  26  s.  Dec.  =  -j-29° 
12'  05".  Between  the  Fly  and  Triangle.  A  6£,  B  10.  Discovered 
by  Struve. 

Pos.  340°  407         Dist  l".903         Epoch  1332.36     Struve. 

';'.••' 


CASSIOPEIA. 

This  constellation  is  situated  26°  N.  of  Androm- 
eda, and  midway  between  it  and  the  North  Polar 
Star.  It  may  be  seen,  from  our  latitude,  at  all 
hours  of  the  night,  and  may  be  traced  out  at  almost 
any  season  of  the  year.  Its  mean  declination  is 
60°  N.  and  its  right  ascension  12°.  It  is  on  our 
meridian  the  22d  November,  but  does  not  sensibly 
change  its  position  for  several  days  ;  for  it  should 
be  remembered  that  the  apparent  motion  of  the  stars 
becomes  slower  and  slower  as  they  approximate 
the  poles. 

Cassiopeia  is  a  beautiful  constellation,  contain- 
ing 55  stars  that  are  visible  to  the  naked  eye  ;  of 
which  one  is  of  the  2d  and  four  are  of  the  3d  mag- 
nitude, and  so  situated  as  to  form,  with  one  or  two 
smaller  ones,  the  figure  of  an  inverted  chair. 

"  Wide  her  stars 

Dispersed,  nor  shine  with  mutual  aid  improved ; 
Nor  dazzle,  brilliant  with  contiguous  flame : 
Their  number  fifty-five." 


46  GEOGRAPHY  OF  THE  HEAVENS. 

Caph,  /3  Cassiopeia,  in  the  garland  of  the  chair,  is 
almost  exactly  in  the  equinoctial  colure,  30°  N.  of 
Alpheratz,  a  Andromeda,  with  which,  and  the  Polar 
Star,  it  forms  a  straight  line.  Caph  is  therefore 
on  the  meridian  the  10th  of  November,  and  one 
hour  past  it  on  the  24th.  It  is  the  westernmost 
star  of  the  bright  cluster.  Schedir,  a  Cassiopeia,  in 
the  breast,  is  the  uppermost  star  of  the  five  bright 
ones,  and  is  5°  S.  E.  of  j3  :  the  other  three  bright  ones, 
forming  the  chair,  are  easily  distinguished,  as  they 
meet  the  eye  at  the  first  glance. 

There  is  an  importance  attached  to  the  position 
of  j3  that  concerns  the  mariner  and  the  surveyor.  '  It 
is  used,  in  connection  with  observations  on  the 
Polar  Star,  for  determining  the  latitude  of  places, 
and  for  discovering  the  magnetic  variations  of  the 
needle. 

It  is  generally  supposed  that  the  North  Polar  Star, 
so  called,  is  the  real  immovable  pole  of  the  heav- 
ens ;  but  this  is  a  mistake.  It  is  so  near  the  true 
pole  that  it  has  obtained  the  appellation  of  the  North 
Polar  Star  ;  but  it  is,  in  reality,  more  than  a  degree 
and  a  half  distant  from  it,  and  revolves  about  the 
true  pole  every  24  hours,  in  a  circle  whose  radius 
is  1°  31'.  It  will  consequently,  in  24  hours,  be 
twice  on  the  meridian,  once  above,  and  once  below 
the  pole  :  and  twice  at  its  greatest  elongation  E. 
and  W. 

The  polar  Star  not  being  exactly  in  the  N.  pole 
of  the  heavens,  but  one  degree  and  31  minutes  on  that 
side  of  it  which  is  towards  Caph,  the  position  of  the 
latter  becomes  important,  as  it  always  shows  on 
which  side  of  the  true  pole  the  polar  star  is. 

There  is  another  important  fact  in  relation  to  the 
position  of  this  star.  It  is  equidistant  from  the  pole, 
nnd  exactly  opposite  another  remarkable  star  in  the 
square  of  the  Great  Bear,  on  the  other  side  of  the 
pole.  It  also  serves  to  mark  a  spot  in  the  starry 


^*  CONSTELLATION  OF  CASSIOPEIA.  47 

heavens,  rendered  memorable  as  being  the  place 
of  a  lost  star.  Two  hundred  and  sixty-six  years 
ago,  a  bright  star  shone  5°  N.  N.  E.  of  Caph,  where 
now  is  a  dark  void  ! 

On  the  8th  of  November,  1572,  Tycho  Brahe  and 
Cornelius  Gemma  saw  a  star  in  the  constellation 
of  Cassiopeia,  which  became  all  at  once,  so  brilliant, 
that  it  surpassed  the  splendor  of  the  brightest  pla- 
nets, and  might  be  seen  even  at  noonday  !  Gradu- 
ally, this  great  brilliancy  diminished,* until  the  1 5th 
of  March,  1573,  when,  without  moving  from  its 
place,  it  became  utterly  extinct. 

Its  color,  during  this  time,  exhibited  all  the  phe- 
nomena of  a  prodigious  flame — first  it  was  of  a 
dazzling  white,  then  of  a  reddish  yellow,  and 
lastly  of  an  ashy  paleness,  in  which  its  light  ex- 
pired. It  is  impossible,  says  Mrs.  Somerville,  to 
imagine  any  thing  more  tremendous  than  a  confla- 
gration that  could  be  visible  at  such  a  distance.  It 
was  seen  for  sixteen  months. 

Some  astronomers  imagined  that  it  would  reap- 
pear again  after  150  years  ;  but  it  has  never  been 
discovered  since.  This  phenomenon  alarmed  all 
the  astronomers  of  the  age,  who  beheld  it ;  and 
many  of  them  wrote  dissertations  concerning  it. 

Rev.  Professor  Vince,  one  of  the  most  learned  and 
pious  astronomers  of  the  age,  has  this  remark : — 
"  The  disappearance  of  some  stars  may  be  the 
destruction  of  that  system  at  the  time  appointed 
by  the  DEITY  for  the  probation  of  its  inhabitants  ; 
and  the  appearance  of  new  stars  may  be  the  forma- 
tion of  new  systems,  for  new  races  of  beings  then 
called  into  existence,  to  adore  the  works  of  their 
Creator." 

Thus,  we  may  conceive  the  Deity  to  have  been 
employed  from  all  eternity,  and  thus  he  may  con- 
tinue to  be  employed  for  endless  ages  ;  forming 
new  systems  of  beings  to  adore  him  ;  and  trans- 


48         GEOGRAPHY  OF  THE  HEAVENS. 

planting  beings  already  formed  into  happier  regions, 
who  will  continue  to  rise  higher  and  higher  in  their 
enjoyments,  and  go  on  to  contemplate  system  after 
system  through  the  boundless  universe. 

LA  PLACE  says  : — "  As  to  those  stars  which  sud- 
denly shine  forth  with  a  very  vivid  light,  and  then 
immediately  disappear,  it  is  extremely  probable  that 
great  conflagrations,  produced  by  extraordinary 
causes,  take  place  on  their  surface.  This  conject- 
ure, is  confirmed  by  their  change  of  color,  which 
is  analogous  to  that  presented  to  us  on  the  earth 
by  those  bodies  which  are  set  on  fire  and  then  gra- 
dually extinguished." 

The  late  eminent  Dr.  Good  also  observes  that — 
"  Worlds  and  systems  of  worlds  are  not  only  perpet- 
ually creating,  but  also  perpetually  disappearing. 
It  is  an  extraordinary  fact,  that  within  the  period 
of  the  last  century,  not  less  than  thirteen  stars,  in 
different  constellations,  seem  to  have  totally  perish- 
ed, and  ten  new  ones  to  have  been  created.  In 
many  instances  it  is  unquestionable,  .that  the  stars 
themselves,  the  supposed  habitation  of  other  kinds 
or  orders  of  intelligent  beings,  together  with  the  dif- 
ferent planets  by  which  it  is  probable  they  were 
surrounded,  have  utterly  vanished,  and  the  spots 
which  they  occupied  in  the  heavens,  have  become 
blanks  !  What  has  befallen  other  systems,  will 
assuredly  befall  our  own.  Of  the  time  and  the 
manner  we  know  nothing,  but  the  fact  is  incontro- 
vertible ;  it  is  foretold  by  revelation  ;  it  is  inscribed 
in  the  heavens ;  it  is  felt  through  the  earth.  Such 
is  the  awful  and  daily  text;  what  then  ought  to  be 
the  comment  ?" 

The  great  and  good  Beza,  falling  in  with  the 
superstition  of  his  age,  attempted  to  prove  that  this 
was  a  comet,  or  the  same  luminous  appearance 
which  conducted  the  magi,  or  wise  men  of  the  East, 


CONSTELLATION  OF  CASSIOPEIA.  49 

into  Palestine,  at  the  birth  of  our  Saviour,  and  that 
it  now  appeared  to  announce  his  second  coming  ! 

About  6°  N.  W.  of  Caph;  the  telescope  reveals 
To  us  a  grand  nebula  of  small  stars,  apparently 
compressed  into  one  mass,  or  single  blaze  of  light, 
with  a  great  number  of  loose  stars  surrounding  it. 

TELESCOPIC  OBJECTS. 

A  LARGE  AJTD  LOOSE  CLUSTER. — A.  R.  =  0  h.  18m.  10  s.  Dec. 
=  -j-  70°  3<y  3".  Registered  by  Sir  Jno.  Herschel,  and  by  him  regarded 
as  a  good  test  for  the  light  and  defining  power  of  a  telescope.  It  is  sit- 
uated between  the  footstool  and  the  knee  of  Cepheus. 

A  CLOSE  DOUBLE  STAR.— A.  R.  =  0  h.  38  m.  58  s.  Dec  =  50° 
34'  2."  Between  Andromeda's  knee  and  the  head  of  Cassiopeia.  A  7  5 
B  9  mag. 

Pos.  147°  2         Dist.  2",3  Epoch   1832.87     Smyth. 

146    25'  2   .24  1847.60     Mitchel. 

The  relationship  is  merely  optical. 

»  CASSIOPEIA.— A.  R,=0  h.  39  m.  27  s.  Dec.  -f-  56°  57'  9".  A 
binary  star  in  the  Cestus  of  Cassiopeia.  A  4  pale  white,  B  7^  purple, 
Discovered  by  Herschel, 

1779,  when  its  position  was  62°  04         Dist.  1 1".27 
1843.19    the  measures  gave  95    08  9  .1       Smyth. 

1847.60  101    20  8    59     Mitchel. 

Mudler  thinks  the  periodic  time  of  this  system  will  be  about  522  years. 

p.  CASSIOPEIA.— A.  R.=0  h.  57  m.  23  s.  Dec.  54°  0'  8".  A  coarse 
triple  star  on  the  right  elbow,  possessed  of  an  extraordinary  proper  mo- 
tion, amounting  to  5".8  in  A.  R.  and  l".55  in  Dec.  per  annum.  In  case 
we  locate  this  star  at  the  distance  from  our  system  due  to  its  magnitude, 
its  hourly  motion  cannot  be  less  than  125,000  miles!  a  quantity  fax  ex- 
ceeding the  velocity  of  the  swiftest  moving  planet. 

A  LOOSE  CLUSTER.— A.  R.  =  0  h.  58  m.  19  s.  Decl.  =  -f  60° 
44'  0"  below  the  right  hip  of  Cassiopeia,  on  the  robe,  one  quarter  way  on 
the  line  joining  y  and  «.  It  was  discovered  by  Miss  Caroline  Herschel, 
in  1783,  and  is  described  by  Sir  William  as  "  a  cluster  of  pretty  compres- 
sed stars.'1 

A  SMALL  DOUBLE  STAR. — A.  R.  =  1  h.  9m.  10  s.  Dec.  =-f-  57° 
56'  9".  Between  the  right  knee  and  elbow  of  Cassiopeia,  A  9.  B  10 
magnitude. — This  object  is  situated  in  the  center  of  a  brilliant  assem- 
blage of  small  stars  discovered  by  Herschel  1787. 

4  CASSIOPEIA. — A.  R.  =  1  h.  14  m.  42  s.     Dec.  =  -j-  67°  17'  5". 
E 


50         GEOGRAPHY  OF  THE  HEAVENS. 

A  fine  triple  star  close  to  the  lower  part  of  Cassiopeia's  throne.  A  4^ 
orange.  B  9  blue.  C  1 1  reddish. 

Discovered  by  Striive. 

Pos.  A.  B.  102°  01'        Dist.  31".9         Epoch  1836.28     Smyth. 
B.  C.  252    36  2  .0  1836.28     Smyth. 

A.  B.  102    37  30  .394  1837.70     Mitchel. 

B.  C.  253    07  32    856  1837.70     Mitchel. 
This  object  may  be  found  between  the  north  star  and  <f  Cassiopeia,  at 

a  little  less  than  one-third  of  the  distance  which  separates  them  from  the 
latter  star. 

AN  OPEN  CLUSTEH.— A.  R.  ==  1  h.  18  m.  51  s.  Dec.  ==  -]-  61° 
27'  8".  On  the  lady's  leg,  half  way  from  i  to  y.  Described  as  "  a 
gathering  of  small  and  large  stars,  with  glimpses  of  star  dust  of  consider- 
able extent." 

A  CLUSTER.— A.  R.  =  1  h.  33  m.  05  s.  Dec.  ==  -f-  61°  01'  9". 
Just  below  the  right  knee  of  Cassiopeia,  mid-way  between  i  and  t  Dis- 
covered by  Herschel.  1787.  It  is  some  2'  or  3'  in  diameter,  and  has  an 
8^  magnitude  star  in  the  center. 

55  CASSIOPIS;.—  A.  R,  =  2  h.  2  m.  0  s.     Dec.  -f  65°  46'  2".     A 

star  with  two  distant  companions — located  very  near  the  position  in  the 
heavens  in  which  the  celebrated  new  star  of  1572  made  its  sudden  and 
brilliant  appearance.  The  first  sight  of  this  most  extraordinary  stranger, 
seems  to  have  been  caught  by  Schiler,  of  Wittemburgh,  as  early  as  the 
6th  of  August,  1 572.  On  the  1 1th  of  November,  following,  the  celebrated 
Tycho  Brahe,  on  returning  to  his  house  from  his  laboratory,  was  surprised 
to  see  some  peasants  gazing  up  hi  the  heavens.  He  soon  discovered  the 
object  of  their  curiosity  to  be  a  brilliant  star,  which  he  had  never  before 
seen.  His  finely  stocked  observatory,  gave  him  an  opportunity  of  obser- 
ving the  stranger  with  great  accuracy.  He  soon  determined  that  it  was 
located  beyond  the  region  of  the  planets,  and  even  among  the  fixed  stars, 
as  it  had  no  sensible  parallax,  and  never  changed  its  position  during  the 
time  it  remained  visible.  The  brilliancy  of  this  object  increased  from  the 
time  of  its  discovery,  until  it  surpassed  that  of  Sirius,  the  brightest  of  all  the 
fixed  stars,  and  even  came  to  be  scarcely  less  than  that  of  Venus,  the  most 
brilliant  planet.  Having  attained  its  maximum  brilliancy,  it  began  to 
decline  by  degrees,  losing  its  splendor,  until  finally,  in  March  1574,  nine- 
teen months  after  its  discovery,  it  disappeared  for  ever  from  the  sight. 
This  being  the  first  change  in  the  region  of  the  fixed  stars,  since  the 
revival  of  letters  in  Europe,  created  a  great  sensation,  and  produced  a 
great  variety  of  published  accounts.  Strange  as  it  may  appear,  at  this 
day,  Tycho  was  ashamed  to  publish  his  observations,  to  the  world,  con- 
sidering it  "  a  disgrace  for  a  nobleman,  either  to  study  such  subjects,  or 
to  publish  them  to  the  world." 

These  new  and  temporary  stars,  are  among  the  inscrutable  works 
of  God.  No  intellect,  however  great,  no  study,  however  profound,  has 
yet  been  able  to  fathom  their  mysterious  coming  and  going.  Some  have 
suggested  the  idea  that  they  are  moving  in  excessively  elongated  orbi^v 


CONSTELLATION  OF  CASSIOPEIA.  51 

whose  principal  axes  are  turned  directly  towards  our  own  system,  and 
that  it  is  only  in  their  nearest  approach  to  the  earth  that  they  become 
visible.  In  consequence  of  the  reported  appearance  of  new  stars,  in  the 
same  region,  in  9  15  and  1264,  Sir  John  Herschel  has  suggested  that  this 
may  be  a  periodical  star,  with  a  return  after  intervals  of  about  three 
hundred  years. 

It  case  we  estimate  the  velocity  of  this  star  in  its  orbit,  by  the  dimi- 
nution of  its  light,  we  shall  find  it  moving  at  so  stupendous  a  rate  as  to 
stun  the  imagination  —  arid  we  are  almost  driven  from  a  theory  requiring 
such  motion.  If  we  yield  to  the  suggestion  of  Bessel,  that  there  exist 
dark  bodies  in  space,  capable  of  modifying  the  movements  of  the  fixed 
stars,  we  might  account  for  the  sudden  appearance  of  new  stars,  by  their 
emergence  from  behind  one  of  these  non-luminous  bodies.  Their  disap- 
pearance, however,  still  remains  an  enigma,  and  we  can  only  yield  and 
acknowledge  that  "  the  heavens  declare  the  glory  of  God  "  —  whether*  man 
can  follow  or  fail. 

A  BK  \UTTFUI  TJIIPLE  STAH.  —  A.  R.  =  2  h.  15  m.  58  s.     Dec.  -f- 

66°  40'  7".  Under  Cassiopeia's  right  foot,  mid-way  between  a.  Persei 
and  y  Cephi.  A  4^  pale  yellow  B  7  lilac.  C  9  blue. 

Pos.  A.  B.  274°  2'        Dist.  2".l          1834.83 
A.  C.    107    1         Dist.  7   .5         1834.83 

No  change  in  position  or  distance  has  been  remarked  since  the 
discovery  by  Herschel,  in  1779. 

A  MULTIPLE  STAR.—  A.  R.  =  23  h.  22  m.  40  s.  Dec.  -f  57°  40'. 
One  of  the  stars  was  discovered  to  be  close  double,  by  the  Rev.  W.  R. 
Dawes,  1840. 

Pos.  2220 


6  CASSIOPEIA.—  A.  R.  =  23  h.  50  m.  55  s.  Dec.  =  -f-  54O  51'  8". 
A  fine  double  star  on  the  left  elbow.  A  6.  B  8.  magnitude.  The  large 
star  is  white,  the  small  one  blue,  with  colors  said  to  be  clear  and  distinct. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    II. 

PISCES.     THE  FISHES. 

Favorably  situated  for  examination  in   October,  No- 
vember and  December. 

THE     FISHES. 
THIS  constellation  is  now  the  first  in  order,  of  the 


52         GEOGRAPHY  OF  THE  HEAVENS. 

12  constellations  of  the  Zodiac,  and  is  usually  rep- 
resented by  two  fishes  tied  a  considerable  distance 
apart,  at  the  extremities  of  a  long  undulating  cord, 
or  ribbon.  It  occupies  a  large  triangular  space  in 
the  heavens,  and  its  outline  at  first  is  somewhat 
difficult  to  trace. 

In  consequence  of  the  annual  precession  of  the 
stars,  the  constellation  Pisces  has  now  come  to  occupy 
the  sign  Aries  ;  each  constellation  having  advanced 
one  whole  sign  in  the  order  of  the  Zodiac.  The 
sun  enters  the  sign  Pisces,  while  the  earth  enters 
that  of  Virgo,  about  the  19th  of  February,  but  he 
does  not  reach  the  constellation  Pisces  before  the  6th 
of  March.  The  Fishes,  therefore,  are  now  called 
the  "  Leaders  of  the  Celestial  Hosts." 

That  loose  assemblage  of  small  stars  directly 
south  of  Merach,  a,  in  the  constellation  of  Androm- 
eda, constitutes  the  Northern  Fish,  whose  mean 
length  is  about  16°,  and  breadth,  7°.  Its  mean 
right  ascension  is  1  h,  and  its  declination  25°  N. 
Consequently,  it  is  on  the  meridian  the  24th  of  No- 
vember ;  and,  from  its  breadth,  is  more  than  a  week 
in  passing  over  it.  The  Northern  Fish  and  its 
ribbon,  beginning  at  a,  Andromedae,may,  by  a  train 
of  small  stars,  be  traced,  in  a  S.  S.  easterly  direction, 
for  a  distance  of  33°,  until  we  come  to  the  star  El 
Rischa,  a  Piscium,  of  the  2d  magnitude,  which  is 
situated  in  the  node,  or  flexure  of  the  ribbon.  This 
is  the  principal  star  in  the  constellation,  and  is 
situated  8°-N.  of  the  equinoctial,  and  53  minutes 
east  of  the  prime  meridian. 

From  a  Piscium  the  ribbon  or  cord  makes  a  sud- 
den flexure,  doubling  back  across  the  ecliptic,  where 
we  meet  with  three  stars  of  the  4th  magnitude 
situated  in  a  row  3°  and  4°  apart,  marked  on  the 
map  f,  «,  8.  From  8  the  ribbon  runs  north  and 
westerly  along  the  Zodiac,  and  terminates  at  the  tail 
of  the  Western  Fish.  The  head  of  the  fish  may  be 


CONSTELLATION  OF  PISCES.  53 

recognised  by  the  star  ]3,  4th  magnitude,  11°  south 
of  a  Pegasi. 

This  part  of  the  ribbon,  including  the  Western 
Fish  at  the  end  of  it,  has  a  mean  declination  of  5° 
N.,  and  may  be  seen  throughout  the  month  of  No- 
vember, passing  the  meridian  slowly  to  the  W., 
near  where  the  sun  passes  it  on  the  1st  of  April. 
Twelve  degrees  W.  of  this  Fish,  there  are  four  small 
stars  situated  in  the  form  of  the  letter  Y.  The  two 
Fishes,  and  the  cord  between  them,  make  two  sides 
of  a  large  triangle,  30°  and  40°  in  length,  the  open 
part  of  which  is  towards  the  N.  W.  When  the 
Northern  Fish  is  on  the  meridian,  the  Western  is 
nearly  two  hours  past  it.  This  constellation  is 
bounded  N.  by  Andromeda,  W.  by  Andromeda  and 
Pegasus,  S.  by  the  Cascade,  and  E.  by  the  Whale, 
the  Ram  and  the  Triangles. 

When,  to  enable  the  pupil  to  find  any  star,  its 
direction  from  another  is  given,  the  latter  is  always 
understood  to  be  on  the  meridian. 

After  a  little  experience  with  the  maps,  even 
though  unaccompanied  by  directions,  the  ingenious 
youth  will  be  able  of  himself,  to  devise  a  great 
many  expedients  and  facilities  for  tracing  the  con- 
stellations, or  selecting  out  particular  stars. 

TELESCOPIC     OBJECTS. 
179  P.     XXIII  Pisdum. 

A   DKT.ICATE  DOUBLE  STAH. — A.  R.  =  23  h.  37  m  49  s.     Dec.  = 
—  0°  37'  4".     Under  the  preceding  Fish,  mid-way  between  Fomalhaux 
and  at  Cassiopeia.     A  8^.     B  15  magnitude. 
Discovered  by  M.  Strive. 

Pos.  228023'          Dist.  2".4l7         Epoch  1832. 50     Struve. 
230    00  3  .000  1833.79     Smyth. 

227    33  2  .702  1847.65     Mitchel. 

These  measures  afford  no  evidence  of  change.     Those  of  Smyth  are 
mere  estimations. 

34  PISCIUM.— A.  R.  =  0  h.  1  m.  53  s.    Dec.  =  -{-  10°  14'  6".    A 

fine  double  star,  near  the  wing  of  Pegasus.    A  6.     B  13£  magnitude. 
Discovered  by  Struve. 
E2 


54  GEOGRAPHY  OF  THE  HEAVENS. 

Pos.  160°  08'         Dist  8".37         Epoch   1 828.73     Struve. 

38  .PISCIUM.— A.  R.  =  0  h.  9  m.  9  s.  Dec.  =  -f-  70  59'  2".  A 
double  star  on  the  tip  of  the  tail  of  the  preceding  Fish.  A  7£.  B  8 
magnitude. 

Discovered  by  Herschel,  1782. 

Pos.   2440  57'        Dist.  =  4".00         Epoch  1 782.68 

235    54  4  .80  18:*7.89     Smyth. 

235    59  4  .646  1817.65     Mitchel. 

These  last  observations  seem  to  decide  the  fixity  of  these  stars. 

49  PISCIUM.— A.  R.  =  0  h.  22  m,  29  s.  Dec.  =  -f- 10°  09'  2".  A 
difficult  double  star,  between  the  wing  of  Pegasus  and  the  right  hand  of 
Andromeda.  A  7.  B  13  magnitude. 

Discovered  by  Struve,  and  thus  measured  by  him  in  November  1828. 

Pos.  107042'         Dist.  13".  26 

55  PISCIUM.— A.  R.  =  0  h.  31  m.  31  s.  Dec.  =  -f-  20°  33'  6". 
Between  the  head  and  right  hand  of  Andromeda.  A  6,  orange.  B  9, 
deep  blue. 

Discovered  by  Striive. 

Pos.  192045'        Dist.  6".37  Epoch  1830.22     Struve. 

191     52  7  .014  1847.65     Mitchel. 

There  is  no  evidence  of  binary  character,  and  this  is  doubtless  an 
optical  duplicity  merely. 

65  PISCIUM.— A.  R.  =  0  h.  41  m.  18  s.    Dec.  =  -f-  26°  50'  3".    A 
dose  double  star  on  the  right  arm  of  Andromeda.     A  6.     B  7  magnitude. 
Discovered  by  Sir  W.  Herschel,  who  made  the  following  measures. 
Pos.  3000.57'         Dist.  4".00  Epoch  1783.15 

298    30  4  .50  1838.17     Smyth. 

297    32  1847.65     Mitchel 

Herschel  thought  there  might  be  physical  connection  between  the  com 
ponents  in  this  set  If  so  the  period  will  be  very  great. 

<p  PISCIUM.— A.  R.  =  1  h.  5  m.  4  s.     Dec  =  -f-  23°  44'  1 '.     On 
the  ventral  fin  of  the  Northern  Fish.     A  6,  B  13  mag. 
Discovered  by  Striive,  and  thus  measured 
Pos.  227°  52'.     Dist.  7".98.    Epoch  1832.06. 

f  PISCIUM.— A.  R.  =  1  h.  5m.  21s.     Dec.  =  -\-  6°  43'  7".     A 

coarse  double  star  on  the  bend  of  the  band  joining  the  two  Fishes.  Mi' d- 
ler  ranks  this  among  the  stars  in  which  there  is  a  probable  retrograde 
motion. 

Pos.  67023'         Dist.  22".  187         Epoch  1781  88     Herschel. 
63°  31'  23".225  1841.57     Mildler. 

A.  R.  — •  1  h.  27  m.  41  s.  Dec.  =  -|-  6°  49'  5".  A  close  double  star 
in  the  space  between  the  two  Fishes  and  the  curve  of  the  Ribbon.  A  6^ 
yellowish,  B  8  pale  white. 

Discovered  by  Herschel,  1792. 

Pos.  200  00'         Dist.  1".467         Epoch  1830.23     Struve. 


CONSTELLATION  OF  PISCES.  55 


A.  R.  =  1  h.  47m.  38s.  Dec.  =  1°  03'  2".  A  close  double  star 
at  the  end  of  the  Ribbon.  A  7,  B  7£. 

Discovered  by  Striive,  and  thus  measured  by  him. 
Pos.  640  42'          Dist.  1".232          Epoch  1831.12. 

«  PISCITTM.— A.  R.  =  1  h  53  m.  46  s.  Dec.  =  1°  59'  3".  A  close 
double  star  at  the  southern  extremity  of  the  Ribbon.  A  5,  pale  green. 
B  6,  blue. 

Pos.  3370  23'          Dist.  Epoch  1781.79     Herschel. 

3320  59'  3».775  1830.93     Bessel. 

3310  48'  3".733  1831.60     Madler 

330°  03'  1847.65     Mitchel. 

Madler,  after  a  full  discussion  of  all  the  observations,  thinks  a  retro- 
grade motion  is  probable,  and  a  period  of  revolution  amounting  to  about 
6000  years.  These  slowly-revolving  objects  require  close  examination  ; 
my  own  measures  go  to  confirm,  in  some  degree,  Midler's  opinion. 

A  FAINT  NEBULA.— A.  R.  =  23h.  06m.  36s.  Dec.  =  -f-  30 
39'  07".  In  the  eye  of  the  preceding  or  western  Fish.  Its  length  is  4  , 
and  its  breadth  1',  according  to  its  discoverer.  It  is  preceded  by  a  fainter 
nebula.  These  objects  are  very  difficult  in  any  but  the  most  powerful 
instruments. 

Discovered  by  Herschel,  1785. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    III. 

ARIES.     THE  RAM. 

Favorably  situated  for  examination  in  November,  De- 
cember, and  January. 

THE   RAM. 

TWENTY-TWO  centuries  ago,  as  Hipparchus  in- 
forms us,  this  constellation  occupied  the  first  sign  in 
the  ecliptic,  commencing  at  the  vernal  equinox. 
But  as  the  constellations  gain  about  50"  on  the 
equinox,  at  every  revolution  of  the  heavens,  they 
have  advanced  in  the  ecliptic  nearly  31°  beyond  it, 
or  more  than  a  whole  sign  :  so  that  the  Fishes  now 


56         GEOGRAPHY  OF  THE  HEAVENS. 

occupy  the  same  place  in  the  Zodiac,  that  Aries  did, 
in  the  time  of  Hipparchus  ;  whence  the  constellation 
Aries  is  now  in  the  sign  Taurus,  Taurus  in  Gemini, 
and  Gemini  in  Cancer,  and  so  on. 

Aries  is  therefore  now  the  second  constellation 
in  the  Zodiac.  It  is  situated  next  east  of  Pisces, 
and  is  midway  between  the  Triangles  and  the  Fly 
on  the  N.  and  the  head  of  Cetus  on  the  S.  It  con- 
tains 66  stars,  of  which,  one  is  of  the  2d,  one  of  the 
3d,  and  several  of  the  4th  magnitudes. 

"  First,  from  the  east,  the  Ram  conducts  the  year ; 

Whom  Ptolemy  with  twice  nine  stirs  adorns, 
%  '          Of  which  two  only  claim  the  second  rank ; 

The  rest,  when  Cynthia  fills  the  sign,  are  lost." 

It  is  readily  distinguished  by  means  of  two  bright 
stars  in  the  head,  about  4°  apart,  the  brightest  being 
the  most  north-easterly  of  the  two.  The  first,  which 
is  of  the  2d  magnitude,  situated  in  the  right  horn,  is 
called  a  Arietis,  or  simply  Arietis  ;  the  other,  which 
is  of  the  3d  magnitude,  lying  near  the  left  horn,  is 
called  Sheratan,  p  Arietis,  and  may  be  known  by 
another  star  of  the  4th  magnitude,  in  the  ear,  1^° 
S.  of  it,  called  Mcsarthim,  y  Arietis,  which  is  the^?^ 
star  in  this  constellation. 

Arietis  and  Sheratan,  are  one  instance  out  of 
many,  where  stars  of  more  than  ordinary  brightness 
are  seen  together  in  pairs,  as  in  the  Twins,  the 
Little  Dog,  &c.,  the  brightest  star  being  commonly 
on  the  east. 

The  position  of  Arietis  affords  important  facilities 
to  nautical  science.  Difficult  to  comprehend  as  it 
may  be,  to  the  unlearned,  the  skillful  navigator  who 
should  be  lost  upon  an  unknown  sea,  or  in  the 
midst  of  the  Pacific  ocean,  could,  by  measuring  the 
distance  between  Arietis  and  the  Moon,  which  often 
passes  near  it,  determine  at  once  not  only  the  spot 
he  was  in,  but  his  true  course  and  distance  to  any 
known  meridian  or  harbor  on  the  earth. 


CONSTELLATION   OF    ARIES.  57 

Lying  along  the  moon's  path,  there  are  nine  con- 
spicuous stars  that  are  used  by  nautical  men  for 
determining  their  longitude  at  sea,  thence  called 
nautical  stars. 

These  stars  are  Arietis,  Aldcbaran,  Pollux,  Regu- 
lus,  Spica  Virginis,  Antares,  Altair,  Fomalhaut,  and 
Mar /cab. 

The  true  places  of  these  stars,  for  every  day  in  the  year,  are  given  in 
the  Nautical  Almanac,  a  valuable  work  published  annually  by  the  hng- 
lish  "  Board  of  Admiralty."  to  guide  mariners  in  navigating  the  seas. 
They  are  usually  published  two  or  three  years  in  advance,  for  the  benefit 
of  long  voyages. 

That  a  man,  says  Sir  John  Herschel,  by  merely  measuring  the  moon's 
apparent  distance  from  a  star,  with  a  little  portable  instrument  held  in  his 
hand,  and  applied  to  his  eye,  even  with  so  unstable  a  footing  as  the  deck 
of  a  ship,  shall  say  positively  within  five  miles,  where  he  is,  on  a  bound- 
less ocean,  cannot  but  appear  to  persons  ignorant  of  physical  astronomy, 
an  approach  to  the  miraculous.  And  yet,  says  he,  the  alternatives  of 
life  and  death,  wealth  and  ruin,  are  daily  and  hourly  staked,  with  perfect 
confidence,  on  these  marvelous  computations. 

Capt.  Basil  Hall,  of  the  royal  navy,  relates  that  he  had  sailed  from  San 
Bias,  on  the  west  coast  of  Mexico,  and  after  a  voyage  of  8000  miles,  occu- 
pying eighty-nine  days,  arrived  off  Rio  Janeiro,  having  in  this  interval 
passed  through  the  Pacific  ocean,  rounded  Cape  Horn,  and  crossed  the 
South  Atlantic  without  making  any  land  or  seeing  a  single  sail  on  the 
voyage.  Arrived  within  a  few  days'  sail  of  Rio,  he  took  a  set  of  lunar 
observations,  to  ascertain  his  true  position,  and  the  bearing  of  the  harbor, 
and  shaped  his  course  accordingly.  "  I  hove  to,"  says  he,  "  at  four  in 
the  morning,  till  the  day  should  break,  and  then  bore  up ;  for  although 
it  was  hazy,  we  could  see  before  us  a  couple  of  miles  or  so.  About  eight 
o'clock  it  became  so  foggy  that  I  did  not  like  to  stand  in  further,  and  was 
just  bringing  the  ship  to  the  wind  again  before  sending  the  people  to 
breakfast,  when  it  suddenly  cleared  off,  and  I  had  the  satisfaction  of  see- 
ing the  great  Sugar-loaf  rock,  which  stands  on  one  side  of  the  harbor's 
mouth,  so  nearly  right  ahead  that  we  had  not  to  alter  our  course  above  a 
point,  in  order  to  hit  the  entrance  of  Rio.  This  was  the  first  land  we 
had  seen  for  three  months,  after  crossing  so  many  seas,  and  being  set 
backwards  and  forwards  by  innumerable  currents  and  foul  winds." 

Arietis  comes  to  the  meridian  about  twelve  mi- 
nutes after  Sheratan,  on  the  5th  December,  near 
where  the  sun  does  in  midsummer.  Arietis,  also, 
is  nearly  on  the  same  meridian  with  Almaack,  in 
the  foot  of  Andromeda,  19°  N.  of  it,  and  culminates 
only  four  minutes  after  it.  The  other  stars  in  this 
constellation  are  quite  small,  constituting  that  loose 


58  GEOGRAPHY  OF  THE  HEAVENS. 

cluster  which  we  see  between  the  Fly  on  the  north, 
and  the  head  of  Cetus  on  the  south. 

When  Arietis  is  on  the  meridian,  Andromeda  and 
Cassiopeia  are  a  little  past  the  meridian,  nearly 
over  head,  and  Perseus  with  the  head  of  Medusa,  is 
as  far  to  the  east  of  it.  Taurus  and  Auriga  are 
two  or  three  hours  lower  down  ;  Orion  appears  in 
the  S.  E.,  and  the  Whale  on  the  meridian, just  below 
Aries,  while  Pegasus  and  the  Swan  are  seen  half 
way  over  in  the  west. 

The  manner  in  which  the  ancients  divided  the  Zodiac  into  twelve 
equal  parts,  was  both  simple  and  ingenious.  Having  no  instrument 
that  would  measure  time  exactly,  "  They  took  a  vessel,  with  a  small  hole 
in  the  bottom,  and  having  filled  it  with  water,  suffered  the  same  to  distill, 
drop  by  drop,  into  another  vessel  set  beneath  to  receive  it,  beginning  at 
the  moment  when  some  star  rose,  and  continuing  till  it  rose  the  next 
following  night,  when  it  would  have  performed  one  complete  revolution 
in  the  heavens.  The  water  falling  down  into  the  receiver  they  divided 
into  twelve  equal  parts  :  and  having  twelve  other  small  vessels  in  readi- 
ness, each  of  them  capable  of  containing  one  part,  they  again  poured  all 
the  water  into  the  upper  vessel,  and  observing  the  rising  of  some  star  in 
the  Zodiac,  at  the  same  time  suffered  the  water  to  drop  into  one  of  the 
small  vessels.  'And  as  soon  as  it  was  full,  they  removed  it,  and  set  an 
empty  one  in  its  place.  Just  as  each  vessel  was  full,  they  took  notice  what 
star  of  the  Zodiac  rose  at  that  time,  and  thus  continued  the  process 
through  the  year,  until  the  twelve  vessels  were  filled." 

Thus  the  Zodiac  was  divided  into  twelve  equal  portions,  corresponding 
to  the  twelve  months,  of  the  year,  commencing  at  the  vernal  equinox. 
Each  of  these  portions  served  as  the  visible  representative  or  sign  of  the 
month  it  appeared  in. 

All  those  stars  in  the  Zodiac  which  were  observed  to  rise  while  the 
first  vessel  was  filling,  were  constellated  and  included  in  the  first  sign, 
and  called  Aries,  an  animal  held  in  great  esteem  by  the  shepherds  of 
Chaldea.  All  those  stars  in  the  Zodiac  which  rose  while  the  second 
vessel  was  filling,  were  constellated  and  included  in  the  second  sign, 
which  for  similar  reasons,  was  denominated  Taurus  ;  and  all  those  stars 
which  were  observed  to  rise  while  the  third  vessel  was  filling,  were  con- 
stellated in  the  third  sign,  and  called  Gemini,  in  allusion  to  the  twin 
season  of  the  flocks. 

Thus  each  sign  of  30°  in  the  Zodiac,  received  a  distinctive  appellation, 
according  to  the  fancy  or  superstition  of  the  inventors ;  which  names  have 
ever  since  been  retained,  although  the  constellations  themselves  have 
since  left  their  nominal  signs  more  than  30°  behind.  The  sign  Aries, 
therefore,  included  all  the  stars  embraced  in  the  first  30°  of  the  Zodiac, 
and  no  more.  The  sign  Taurus,  .in  like  manner,  included  all  those  stars 
embraced  in  the  next  30°  of  the  Zodiac,  or  those  between  30°  and  t>0°, 


CONSTELLATION    OF   PISCES.  59 

and  so  of  the  rest.  Of  those  who  imagine  that  the  twelve  constellations 
of  the  Zodiac  refer  to  the  twelve  tribes  of  Israel,  some  ascribe  Aries  to 
the  tribe  of  Simeon,  and  others,  to  Gad. 

During  the  campaigns  of  the  French  army  in  Egypt,  General  Dessaix 
discovered  among  the  ruins  at  Dendera,  near  the  banks  of  the  Nile,  the 
great  templ6  supposed  by  some  to  have  been  dedicated  to  Isis,  the  female 
deity  of  the  Egyptians,  who  believed  that  the  rising  of  the  Nile  was 
occasioned  by  the  tears  which  she  continually  shed  for  the  loss  of  her 
brother  Osiris,  who  was  murdered  by  Typhon. 

Others  suppose  this  edifice  was  erected  for  astronomical  purposes,  from 
the  circumstance  that  two  Zodiacs  were  discovered  drawn  upon  the 
ceiling,  on  opposite  sides.  On  both  these  Zodiacs  the  equinoctial  points 
are  in  Leo,  and  not  in  Aries ;  from  which  it  has  been  concluded,  by  those 
who  pertinaciously  endeavor  to  array  the  arguments  of  science  against 
the  chronology  of  the  Bible  and  the  validity  of  the  Mosaic  account,  that 
these  Zodiacs  were  constructed  when  the  sun  emered  the  sign  Leo,  which 
must  have  been  9720  years  ago,  or  4000  years  before  the  inspired  account 
of  the  creation.  The  infidel  writers  in  France  and  Germany,  make  it 
io,000  years  before.  But  we  may  "  set  to  our  seal,"  that  whatever  is 
true  in  fact  and  correct  in  inference  on  this  subject  will  be  found,  in  the 
end,  riot  only  consistent  with  the  Mosaic  record,  but  with  the  common 
meaning  of  the  expressions  it  uses. 

The  discovery  of  Champollion  has  put  this  question  for  ever  at  rest ; 
and  M.  Latronne,  a  most  learned  antiquary,  has  very  satisfactorily  de- 
monstrated that  these  Egyptian  Zodiacs  are  merely  the  horoscopes  of 
distinguished  personages,  or  the  precise  situation  of  the  heavenly  bodies 
in  the  Zodiac  at  their  nativity.  The  idea  that  such  was  their  purpose 
and  origin,  first  suggested  itself  to  this  gentleman  on  finding,  in  the  box 
of  a  mummy,  a  similar  Zodiac,  with  such  inscriptions  and  characters  as 
determined  it  to  be  the  horoscope  of  the  deceased  person. 

Of  all  the  discoveries  of  the  antiquary  among  the  relics  of  ancient 
Greece,  the  ruins  of  Palmyra,  the  gigantic  pyramids  of  Egypt,  the 
temples  of  their  gods,  or  the  sepulchres  of  their  kings,  scarcely  one  so 
aroused  and  riveted  the  curiosity  of  the  learned,  as  did  the  discovery  of 
Champollion  the  younger,  which  deciphers  the  hieroglyphics  of  ancient 
Egypt. 

The  potency  of  this  invaluable  discovery  has  already  been  signally 
manifested  in  settling  a  formidable  controversy  between  the  champions 
of  infidelity  and  those  who  maintain  the  Bible  account  of  the  creation. 
It  has  been  shown  that  the  constellation  Pisces,  since  the  days  of  Hip- 
parchus,  has  come,  by  reason  of  the  annual  precession,  to  occupy  the 
same  apparent  place  in  the  heavens  that  Aries  did  two  thousand  years 
ago.  The  Christian  astronomer  and  the  infidel  are  perfectly  agreed  as 
to  the  fact,  and  the  amount  of  this  yearly  gain  in  the  apparent  motion 
of  the  stars.  They  both  believe,  and  both  can  demonstrate,  that  the  fixed 
stars  have  gone  forward  in  the  Zodiac,  about  50"  of  a  degree  in  every 
revolution  of  the  heavens  since  the  creation ;  so  that  were  the  world  to 
light  upon  any  authentic  inscription  or  record  of  past  ages,  which  should 
give  the  true  position  or  longitude  of  any  particular  star  at  that  time,  it 
would  be  easy  tp  fix  an  unquestionable  date  to  such  a  record.  Accord- 


60         GEOGRAPHY  OF  THE  HEAVENS. 

ingly,  when  the  famous  "  Egyptian  Zodiacs,"  which  were  sculptured  on 
the  walls  of  the  temple  at  Dendera,  were  brought  away  en  masse,  and 
exhibited  in  the  Louvre  at  Paris,  they  enkindled  a  more  exciting  interest 
in  the  thousands  who  saw  them,  than  ever  did  the  entrance  of  Napoleon. 
M  Educated  men  of  every  order,  and  those  who  had  the  vanity  to  think 
themselves  such,"  says  the  commentator  of  Champollion,  "  rushed  to  be- 
hold the  Zodiacs.  These  Zodiacs  were  immediately  published  and  com- 
mented upon,  with  more  or  less  good  faith  and  decorum.  Science  struck 
out  into  systems  very  bold  ;  and  the  spirit  of  infidelity,  seizing  upon  the 
discovery,  flattered  itself  with  the  hope  of  drawing  from  thence  new  sup- 
port. It  was  unjustifiably  taken  for  granted,  that  the  ruins  of  Egypt 
furnished  astronomy  with  monuments,  containing  observations  that  ex- 
hibited the  state  of  the  heavens  in  the  most  remote  periods.  Starting 
with  this  assumption,  a  pretense  was  made  of  demonstrating,  by  means 
of  calculations  received  as  infallible,  that  the  celestial  appearances  assign- 
ed to  these  monuments  extended  back  from  forty  to  sixty-five  centuries  ; 
that  the  Zodiacal  system  to  which  they  must  belong,  dated  back  fifteen 
thousand  years,  and  must  reach  far  beyond  the  limits  assigned  by  Moses 
to  the  existence  of  the  world."  Among  those  who  stood  forth  more  or 
less  bold  as  the  adversaries  of  revelation,  the  most  prominent  was  M. 
Dupuis,  the  famous  author  of  Uorigine  de  tous  les  Cultes. 

The  infidelity  of  Dupuis  was  spread  about  by  means  of  pamphlets,  and 
the  advocates  of  the  Mosaic  account  were  scandalized  "  until  a  new 
Alexander  arose  to  cut  the  Gordian  knot,  which  men  had  vainly  sought 
to  untie.     This  was  Champollion  the  younger,  armed  with  his  discovery."  ^ 
The  hieroglyphics  now  speak  a  language  that  all  can  understand,  and  no  * 
one  gainsay.     "  The  Egyptian  Zodiacs,  then,"  says  Latronne,  "  relate  in 
no  respect  to  astronomy,  but  to  the  idle  phantasies  of  judicial  astrology, 
as  connected  with  the  destinies  of  the  emperors  who  made  or  completed 
them." 

TELESCOPIC    OBJECTS. 

A  CLOSE  DOUBLE  STAR. —  A.  R.  =  1  h.  41  m.  19  s.     Dec.  =  -j- 
210  28'  7".     On  the  horn  of  Aries.     A  6,  yellow.     B  8,  blue. 
Discovered  by  Herschel. 

Pos.   1720  26'         Dist.  3".378         Epoch  1823.98     Struve. 
169    54  2.400  1836.11     Smyth. 

y  ARIETIS.— A.  R.  =  1  h.  44  m.  45  s.     Dec.  =-f-  18°  30'  5".     In 
the  lower  bend  of  the  Ram's  horn.     A  4£,  B  5.    This  is  the  first  double 
star  ever  detected.     Less  than  one  hundred  years  have  elapsed,  and  now 
they  are  numbered  by  thousands. 
Discovered  by  Dr.  Hook   1764. 
Madler  thinks  motion  is  probable. 

Pos.   183°  55'        Dist.  10".172         Epoch  1779.63     Herschel. 

179    30  8  .957  1831.79     Strive. 

178    20  8  .819  1841.78     Madler. 

175    37  9  .184  1847.65     MitcheL 

If  we  are  to  receive  these  observations  as  conclusive  of  periodic  revolu- 


CONSTELLATION  OF  PISCES.  61 

tion,  the  mighty  year  of  these  two  suns  cannot  fall  much  short  of  four 
thousand  of  our  years. 

A  ROUND  NEBULA.— A.  R.  =  1  h.  50  m.  34  s.  Dec.  =  -j-  igo 
13'  6".  Following  y  on  the  neck  of  Aries.  It  is  quite  large  but  faint. 

A  QUADRUPLE  STAR — A.  R.  =  1  h.  50  m.  43  s.  Dec.  =-J-  20° 
16'  7".  Under  the  ear  of  Aries.  A  6,  B  15,  C  10,  D  9  magnitude. 
Measures  of  A  and  B  only  are  given.  The  other  distances  are  great. 

A  to  B  Pos.  =  530  32'     Dist.  2".  370     Epoch  1832.42     Struve. 

10  ARIETIS.— A.  R.  =  1  h.  54  m.  35  s.    Dec.  =  -f-  25©  09'  7". 
Over  the  head  of  the  Ram.     A  6£,  B  8$. 
Discovered  by  Struve. 
Pos.  250  ir         Dist.  1".98         Epoch  1833.05     Struve. 

ir  ARIETIS.— A.  R.  ==  2  h.  40  m.  22  s.  Dec.  -f  16°  47'  8".  On 
the  haunch  of  Aries.  A  beautiful  triple  set.  A  5,  B  8£,  C  11 
magnitude. 

Discovered  by  Sir  W.  Herschel,  October  1782. 

«  ARIETIS.— A.  R.  =  20  h.  50m.  04s.  Dec.  =  -f-  20O  41'  08"- 
A  very  close  double  star  at  the  root  of  the  tail  of  Aries.  A  5,  B  6^. 
Discovered  by  Struve,  and  reckoned  by  him  as  among  his  closest,  and 
marked  "pervicinse."  It  was  one  of  the  first  tests  employed  after  the 
erection  of  the  Cincinnati  Refractor,  and  so  easily  separated  as  to  excite 
the  suspicion  that  the  distance  between  the  components  has  been  in- 
creasing. This  is  confirmed  by  the  following  measures. 

Pos.  1880  50'         Dist.  0".547         Epoch  1830.16     Struve. 
196     11  0  .764  1841.87     Mudler. 

32  ARIETIS.-^A.  R.  =  2  h.  56  m.  05  s.  Dec.  =  -f-  24O  37'  07". 
A  triple  set  between  the  tail  of  Aries  and  the  Fly.  A  6£,  B  7,  C  15, 
mag.  Discovered  by  Struve. 

A  to  B  Pos.  2660  34'  08"     Dist.  0".45     Epoch  1841.87     Mudler. 

A  to  C          355     00   00  5  .00  1835.88     Smyth. 

A  CLOSE  DOUBLE  STAB.— A.  R.  =  3  h.  1 4  m.  06  s.     Dec.  =  -\-  20<> 
23'  07".    Following  the  tail  of  Aries.     A  8,  B  9,  mag. 
Discovered  by  Struve. 
Pos.  930  42'        Dist.  0".75        Epoch  1827.16    Struve. 


62  GEOGRAPHY  OF  THE   HEAVENS. 

DIRECTIONS  FOR  TRACING   THE  CONSTELLATIONS  ON 

MAP    NO.    IV. 

CETUS — THE  WHALE. 

PART  OF  ERIDANUS — THE  RIVER  Po. 

Favorably  situated  for  examination  in  October •,  Novem- 
ber,  December,  and  January. 

THE    WHALE. 

As  the  whale  is  the  chief  monster  of  the  deep. 
and  the  largest  of  the  aquatic  race,  so  is  it  the 
largest  constellation  in  the  heavens.  It  occupies  a 
space  of  50°  in  length,  E.  and  W.,  with  a  mean 
breadth  of  20°  from  N.  to  S.  It  is  situated  below 
Aries  and  the  Triangles,  with  a  mean  declination 
of  12°  S.  It  is  represented  as  making  its  way  to 
the  east,  with  its  body  below,  and  its  head  elevated 
above  the  equinoctial;  and  is  six  weeks  in  passing 
the  meridian.  Its  tail  comes  to  the  meridian  on 
the  10th  of  November,  and  its  head  leaves  it  on  the 
22d  of  December. 

This  constellation  contains  ninety-seven  stars ; 
three  of  the  2d  magnitude,  nine  of  the  3d,  and  seve- 
ral of  the  4th.  The  head  of  Cetus  may  be  readily 
distinguished,  about  20°  S.  E.  of  Aries,  by  means 
of  five  remarkable  stars,  4°  and  5°  apart,  and  so 
situated  as  to  form  a  regular  pentagon.  The 
brightest  of  these  is  Menkar,  a  Ceti,  of  the  2d  mag- 
nitude, in  the  nose  of  the  Whale.  It  occupies  the  S. 
E.  angle  of  the  figure.  It  is  3j°  N.  of  the  equinoc- 
tial, and  15°  E.  of  El  Rischa,a  Piscium,  in  the  bight 
of  the  cord  between  the  Two  Fishes.  It  is  directly 
37°  S.  of  Algol,  and  nearly  in  the  same  direction 
from  the  Fly.  It  makes  an  equilateral  triangle 
with  Arietis  and  the  Pleiades,  being  distant  from 


CONSTELLATION  OF  CETUS.  63 

each  about  23°  S.,  and  may  otherwise  be  known  by 
a  star  of  the  3d  magnitude  in  the  mouth',  3°  W.  of 
it,  called  y,  placed  in  the  south  middle  angle  of  the 
pentagon. 

v  Is  a  star  of  the  4th  magnitude,  4°  N.  W.  of  y, 
and  these  two  constitute  the  S.  W.  side  of  the  pen- 
tagon in  the  head  of  the  Whale,  and  the  N.  E.  side 
of  a  similar  oblong  figure  in  the  neck. 

Three  degrees  S.  S.  W.  of  y,  is  another  star  of 
the  4th  magnitude, in  the  lower  jaw,  marked  6,  con- 
stituting the  east  side  of  the  oblong  pentagon  ;  and 
6°  S.  W.  of  this,  is  a  noted  star  in  the  neck  of  the 
Whale, called  Mira,  marked  o,  or  the  "  wonderful  star 
of  1596,"  which  forms  the  S.  E.  side.  This  variable 
star  was  first  noticed  as  such  by  Fabricius,  on  the 
13th  of  August,  1596.  It  changes  from  a  star  of 
the  2d  magnitude  so  as  to  become  invisible  once  in 
334  days,  or  about  seven  times  in  six  years.  Her- 
schel  makes  its  period  331  days,  10  hours,  and  19 
minutes ;  while  Hevelius  assures  us  that  it  once 
disappeared  for  four  years  ;  so  that  its  true  period, 
perhaps,  has  not  been  satisfactorily  determined. 

The  whole  number  of  stars  ascertained  to  be  variable,  amounts  to  only 
15  ;  while  those  which  are  suspected  to  be  variable  amount  to  37. 

Mira  is  7°  S.  S.  E.  of  a  Piscium,  in  the  bend  or 
knot  of  the  ribbon  which  connects  the  Two  Fishes. 
Ten  degrees  S.  of  Mira,  are  four  small  stars,  in  the 
breast  and  paws,  about  3°  apart,  which  form  a 
square,  the  brightest  being  on  the  east.  Ten  de- 
grees S.  W.  of  Mira,  is  a  star  of  the  3d  magnitude 
in  the  heart,  called  Eaten  Kaitos,  £  Ceti,  which  makes 
a  scalene  triangle  with  two  other  stars  of  the  same 
magnitude  7°  and  10°  west  of  it ;  also,  an  equilateral 
triangle  with  Mira  and  the  easternmost  one  in  the 
square. 

A  great  number  of  geometrical  figures  may  be  formed  from  the  stars 
in  this,  and  in  most  of  the  other  constellations,  merely  by  reference  to  the 


64         GEOGRAPHY  OF  THE  HEAVENS. 

maps ;  but  it  is  better  that  the  student  should  exercise  his  own  ingenuity 
in  this  way  with  reference  to  the  stars  themselves,  for  whr n  once  he  has 
constructed  a  group  into  any  letter  or  figure  of  his  own  invention,  he 
never  will  forget  it 

The  teacher  should  therefore  require  his  class  to  commit  to  writing  the 
result  of  their  own  observations  upon  the  relative  position,  magnitude  and 
figures  of  the  principal  stars  in  each  constellation.  One  evening's  exer- 
cise in  this  way  will  disclose  to  the  student  a  surprising  multitude  of 
crosses,  squares,  triangles,  arcs  and  letters,  by  which  he  will  be  better 
able  to  identify  and  remember  them,  than  by  any  instructions  that  could 
be  given.  » 

For  example :  o  and  £  in  the  Whale,  about  10°  apart,  make  up  the 
S.  E.  or  shorter  side  of  an  irregular  square,  with  A  in  the  node  of  the 
Ribbon,  and  another  star  in  the  Whale  as  far  to  the  right  of  £,  as  a  is 
above  o.  Again, 

There  are  three  stars  of  equal  magnitude,  forming  a  straight  line  W. 
of  Baten;  from  which,  to  the  middle  star  is  10°,  thence  to  the  W.  one 
12£;  and  8°  or  9°  S.  of  this  line,  in  a  triangular  direction,  is  a  bright 
star  of  the  second  magnitude  in  the  coil  of  the  tail,  called  Diphda,  or  /. 

TELESCOPIC    OBJECTS. 

12  CETI.— A.  R.  =  Oh.  21  m.  53s.  Dec.  =  —  4°  50'  06".  A 
difficult  double  star,  between  the  Whale's  tail  and  the  Southern  Fish. 
A  6,  yellow ;  B  15,  blue.  Position  and  distance  estimated  as  follows,  in 
the  Bedford  Catalogue : 

Pos.  1800  56'          Dist.  6".5         Epoch  1837.89. 

A  LONG  NARROW  NEBULA. — A.  R.  =  0  h.  39  m.  45  s.     Decl.  =  — 
26°  10'.     Near  the  boundary  of  the  Apparatus  Sculptoris. 
Discovered  by  Miss  Herschel,  in  1783. 

42  CETI.— A,  R.  =  1  h.  llm.  38  s.     Dec.  =  —  lo  21'.     A  close 
double  star,  between  the  whale's  back  and  the  band  of  Pisces. — A  6, 
B  8  mag.     Discovered  by  Striive  and  marked  among  his  "  Vicinae  "  stars. 
Pos.  =  334°  30'         Dist.  I'M 77        Ep.  1836.91     Striive. 

61  CETI.— A.  R.  =  1  h.  55  m.  37  s.  Dec.  =  —  lo  06'  5".  A 
double  star  on  the  back  of  the  head  of  Cetus.  A  7,  B  8£  mag.  Dis- 
covered by  Striive,  who  reports  the  following  measures. 

Pos.  =  2500  00'         Dist.  4".78.         Epoch  1832.36. 

o  CETI.  MIRA.— A.  R.  =  2  h.  11  m.  16  s.  Dec.  =  —  30  42'  3". 
A  remarkable  variable  star,  with  a  distant  companion,  on  the  middle  of 
the  whale's  neck.  It  is  the  first  of  these  wonderful  objects  ever  discover- 
ed, and  was  noticed  by  David  Fabricius  as  early  as  1596.  It  becomes  as 
bright  as  the  second  magnitude,  and  then  decreases  to  invisibility.  Her- 
schel estimates  its  period  at  33 1  days  1 0  hours  1 9  minutes.  Its  maxi- 
mum brilliancy  is  attained  about  the  first  of  October  at  this  time.  The 
color  of  this  star  is  also  said  to  vary  with  the  magnitude. 


CONSTELLATION  OF   CETUS.  65 

A  PLANETARY  NEBULA.— A.  R.  =  2  h  19  m.  25  s.  Dec.  =  —  1° 
51'  6".  In  the  middle  of  the  whale's  neck.  Discovered  by  Herschel, 
1T85. 

v  CETI.— A.  R.  =  2  h.  27  m.  29  s.  Dec.  =  -}-  4°  53'  5".  A 
double  star  in  the  whale's  eye.  A  4|,  yellow,  B  1ft,  blue. — This  is  one 
of  Struve's  "  difficiles  ".  He  reports  the  following  measures  : 

Pos.  83030'         Dist7".725         Ep.  1831.92. 

84  CETI.— A.  R.  =  2  h.  33  m.  02  s.    Dec.  =  —  1°  22'  7".     A 

difficult  object  like  the  preceding,  on  the  whale's  under  jaw.  Striive, 
its  discoverer  furnishes  these  measures  : 

Pos.  3340  37'         Dist.  4".855         Ep.  1831.90. 

A  ROUKD  NEBULA A.  R.  =  2  h.  34m.  30s.  Dec.  =  —  0° 

41'  01".  On  the  Whale's  lower  jaw.  Examined  by  Herschel,  and 
placed  in  the  910th  order  of  distances;  that  is,  910  times  more  remote 
than  the  fixed  stars  of  the  first  magnitude. 

Discovered  by  Messier. 

y  CETI.— A.  R.  =  2  h.  35  m.  01".  Decl.  =  -f  2O  33'  05".  A 
beautiful  close  double  star,  in  the  Whale's  mouth.  The  Bedford  Cata- 
logue regards  the  •<  fixity"  of  the  components  as  established*;  while 
Midler  thinks  an  increasing  motion  certain,  with  a  period  of  about  569 
years.  The  following  measures  are  reported : 

Pos.  =  283°   12'         Dist.  2".835         Epoch  1825  42     Strdve. 
287     06  2  .680  1833.36 

293     37  2  .946  1841.14    Mudler. 

AN  OVAL  NEBULA.— A.  R.  =  2  h.  38  m  08  s.  Decl.  =  —  8°  15' 
1".  On  the  breast  of  the  Whale.  "  It  is  pale,  though  distinct,  and 
brightens  at  the  center." 

Discovered  by  Herschel,  1785. 

94  CKTI.— A.  R.  =  3  h.   04  m.  38  s.     Decl.  =  —  1°  47'  09".     A 
difficult  double  star,  in  the  top  of  the  Whale's  tongue.     A  5^,  B  16,  mag. 
Discovered  by  Sir  John  Herschel. 

;:•-•* 

F* 


GEOGRAPHY  OF  THE  HEAVENS. 
DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    V. 

TAURUS — THE  BULL. 
ORION. 

PART  OF  ERIDANUS — THE  RIVER  Po. 
Favorably  situated  for  examination  in  December ,  Ja- 
,  February  and  March. 

TAURUS.      . 

THE  BULL  is  represented  in  an  attitude  of  rage, 
as  if  about  to  plunge  at  Orion,  who  seems  to  invite 
the  onset  by  provocations  of  assault  and  defiance. 
Only  the  head  and  shoulders  of  the  animal  are  to 
be  seen ;  but  these  are  so  distinctly  marked  that 
they  cannot  be  mistaken.  Taurus  is  now  the  se- 
cond sign  and  third  constellation  of  the  zodiac ;  but 
anterior  to  the  time  of  Abraham,  or  more  than  4000 
years  ago,  the  vernal  equinox  took  place,  and  the 
year  opened  when  the  sun  was  in  Taurus  ;  and  the 
Bull,  for  the  space  of  2000  years,  was  the  prince 
and  leader  of  the  celestial  host.  The  Ram  suc- 
ceeded next,  and  now  the  Fishes  lead  the  year. 
The  head  of  Taurus  sets  with  the  sun  about  the 
last  of  May,  when  the  opposite  constellation,  the 
Scorpion,  is  seen  to  rise  in  the  S.  E.  It  is  situated 
between  Perseus  and  Auriga  on  the  north,  Gemini 
on  the  east,  Orion  and  Eridanus  on  the  south,  and 
Aries  on  the  west,  having  a  mean  declination  of 
16°  north. 

It  contains  141  visible  stars,  including  two  re- 
markable clusters,  called  the  PLEIADES  and  HYADES. 
The  first  is  now  on  the  shoulder,  and  the  latter  in 
the  face  of  the  Bull. 

The  Pleiades,  according  to  fable,  were  the  seven 
daughters  of  Atlas  and  the  nymph  Pleione,  who 


CONSTELLATION  OF  TAURUS.  67 

were  turned  into  stars,  with  their  sisters  the  Hyades, 
on  account  of  their  amiable  virtues  and  mutual 
affection.  » 

Thus  we  everywhere  find  that  the  ancients,  with  all  their  barbarism 
and  idolatry,  entertained  the  belief  that  unblemished  virtue  and  a  merito- 
rious life  would  meet  their  reward  in  the  sky.  Thus  Virgil  represents 
Magnus  Apollo  as  bending  from  the  sky  to  address  the  youth  lulus : — 

"  Macte  nova  virtute  puer  :  sic  itur  ad  astra ; 
Diis  genite,  et  geniture  Deos." 

"Go  on,  spotless  boy,  in  the  paths  of  virtue  ;  it  is  the  way  to  the  stars ; 
offspring  of  the  gods  thyself— so  shalt  thou  become  the  father  of  gods." 

Our  disgust  at  their  superstitions  may  be  in  some  measure  mitigated, 
by  seriously  reflecting,  that  had  some  of  these  personages  lived  in  our 
day,  they  had  been  ornaments  in  the  Christian  church,  and  models  of 
social  virtue. 

The  names  of  the  Pleiades  are  Alcyone,  Merope, 
Maia,  Electra,  Tayeta,  Sterope  and  Celeno.  Merope 
was  the  only  one  who  married  a  mortal,  and  on 
that  account  her  star  is  dim  among  her  sisters. 

Although  but  six  of  these  are  visible  to  the  naked 
eye,  yet  Dr.  Hook  informs  us  that,  with  a  twelve 
feet  telescope,  he  saw  78  stars  ;  and  Rheita  affirms 
that  he  counted  200  stars  in  this  small  cluster. 

The  most  ancient  authors,  such  as  Homer,  Attains,  and  Geminus, 
counted  only  six  Pleiades ;  but  Simonides,  Varro.  Pliny,  Aratus,  Hip- 
parchus,  and  Ptolemy,  reckon  them  seven  in  number ;  and  it  was  as- 
serted, that  the  seventh  had  been  seen  before  the  burning  of  Troy  ;  but 
this  difference  might  arise  from  the  difference  in  distinguishing  them  with 
the  naked  eye. 

The  Pleiades  are  so  called  from  the  Greek  word, 
TtXfftv, pleein,  to  sail;  because,  at  this  season  of  the 
year,  they  were  considered  *'  the  star  of  the  ocean" 
to  the  benighted  mariner.  Alcyone,  of  the  3d  mag- 
nitude, being  the  brightest  star  in  this  cluster,  is 
sometimes  called  the  light  of  the  Pleiades.  The  other 
five  are  principally  of  the  4th  and  5th  magnitudes. 

The  Pleiades,  or  as  they  are  more  familiarly 
termed,  the  seven  stars,  come  to  the  meridian  10 
minutes  before  9  o'clock,  on  the  evening  of  the  1st 
of  January,  and  may  serve,  in  place  of  the  sun,  to 


68         GEOGRAPHY  OF  THE  HEAVENS. 
v^! 

indicate  the  time,  and  as  a  guide  to  the  surrounding 
stars. 

According  to  Hesiod,  who  wrote  about  900  years  before  the  birth  of 
our  Saviour,  the  heliacal  rising  of  the  Pleiades  took  place  on  the  llth  of 
May,  about  the  time  of  harvest. 

"  When,  Atlas-born,  the  Pleiad  stars  arise 
Before  the  sun  above  the  dawning  skies, 
'Tis  time  to  reap ;  and  when  they  sink  below 
The  morn-illumin'd  west,  'tis  time  to  sow." 

Thus,  in  all  ages,  have  the  stars  been  observed  by  the  husbandman, 
for  "  signs  and  for  seasons." 

Pliny  says  that  Thales,  the  Miletan  astronomer,  determined  the  cos- 
mical  setting  of  the  Pleiades  to  be  25  days  after  the  autumnal  equinox. 
This  would  make  a  difference  between  the  setting  at  that  time  and  the 
present,  of  35  days,  and  as  a  day  answers  to  about  59'  of  the  ecliptic, 
these  days  will  make  34°  25'.  This,  divided  by  the  annual  precession 
(50f ),  will  give  2465  years  since  the  time  of  Thales.  Thus  does 
astronomy  become  the  parent  of  chronology. 

If  it  be  borne  in  mind  that  the  stars  uniformly  rise,  come  to  the  meri- 
dian, and  set  about  four  minutes  earlier  every  succeeding  night,  it  will  IK? 
very  easy  to  determine  at  what  time  the  seven  stars  pass  the  meridian  on 
any  night  subsequent  or  antecedent  to  the  1st  of  January.  For  exam- 
ple :  at  what  time  will  the  seven  stars  culminate  on  the  5th  of  January "! . 
Multiply  the  five  days  by  four,  and  take  the  result  from  the  time  they 
culminate  on  the  1st,  and  it  will  give  thirty  minutes  after  eight  o'clock  in 
the  evening. 

The  Pleiades  are  also  sometimes  called  Vergilice, 
or  the  "  Virgins  of  spring  ; "  because  the  sun  enters 
this  cluster  in  the  "  season  of  blossoms,"  about  the 
18th  of  May.  He  who  made  them  alludes  to  this 
circumstance  when  he  demands  of  Job  :  "  Canst 
thou  bind  the  sweet  influences  of  the  Pleiades," 
&c. — [Job  xxxviii,  31.] 

The  Syrian  name  of  the  Pleiades  is  Succoth,  or  Succofh-Benotk,  de- 
rived from  a  Chaldaic  word,  which  signifies  "  to  speculate,  to  observe," 
and  the  "Men  of  Succoth"  (2  Kings  xvii,  30),  have  been  thence 
considered  observers  of  the  stars. 

The  Hyades  are  situated  11°  S.  E.  of  the  Pleiades, 
in  the  face  of  the  Bull,  and  may  be  readily  dis- 
tinguished by  means  of  five  stars  so  placed  as  to 
form  the  letter  V.  The  most  brilliant  star  is  on 


CONSTELLATION  OF  TAURUS.  69 

the  left,  in  the  top  of  the  letter,  and  called  Aldeba- 
ran, a  Tauri,  from  which  the  moon's  distance  is 
computed. 

"  A  star  of  the  first  magnitude  illumes 
His  radiant  head  ;  and  of  the  second  rank, 
Another  beams  not  far  remote." 

Aldebaran  is  of  Arabic  origin,  and  takes  its  name 
from  two  words  which  signify,  "  He  went  before,  or 
led  the  way  " — alluding  to  that  period  in  the  history 
of  astronomy  when  this  star  led  up  the  starry  host 
from  the  vernal  equinox.  It  comes  to  the  meridian 
at  nine  o'clock  on  the  10th  of  January,  or  48£ 
minutes  after  Alcyone, »?  Tauri,  on  the  1st.  When 
Aries  is  about  27°  high,  Aldebaran  is  just  rising  in 
the  east.  So  MANILIUS  : — 

"  Thus  when  the  Ram  hath  doubled  ten  degrees, 
And  join'd  seven  more,  then  rise  the  Hyades." 

A  line  15£°  E.  N.  E.  of  Aldebaran  will  point  out 
a  bright  star  of  the  2d  magnitude  in  the  extremity 
of  the  northern  horn,  marked  j3  or  El  Nath ;  (this 
star  is  also  in  the  foot  of  Auriga,  and  is  common  to 
both  constellations.)  From  j3  in  the  northern  horn, 
to  £  in  the  tip  of  the  southern  horn,  it  is  8°,  in  a 
southerly  direction.  This  star  forms  a  right  angle 
with  a  and  p.  /3  and  £.  both,  in  the  button  of  the 
horns,  are  in  a  line  nearly  north  and  south,  8° 
apart,  with  the  brightest  on  the  north.  That  very 
bright  star  17£°  N.  of  j3,  is  Capella  a,  in  the  constel- 
lation Auriga. 

This  map  contains  the  most  brilliant,  and  on 
all  accounts,  the  most  interesting  portions  of  the 
heavens.  According  to  the  investigations  of  Striive, 
this  region  is  nearer  to  our  sun  and  system  than 
any  other  portion  of  the  celestial  sphere,  as  will  be 
more  fully  developed  hereafter.  Besides  this,  Alcy- 
one is  regarded  as  the  great  center  of  the  millions 


70  GEOGRAPHY  OF   THE  HEAVENS. 

of  stars   clustered   together  and  forming  the  Milky 
Way. 

This  region,  on  account  of  its  splendor,  arid  the 
remarkable  configurations  of  its  stars,  forms  an  ad- 
mirable point  in  beginning  the  study  of  the  heavens. 

TELESCOPIC     OBJECTS. 

7  TAURI.— A.  R.  =  3  h.  24  m.  58  s.  Dec.  =  -f-  23°  55'  4".  A 
triple  star  on  the  back  of  Taurus.  A  6,  B  6£,  C  11  magnitude. 

Discovered  by  Struve,  and  two  of  the  components  are  among  his 
"  vicinessemae,''  or  close  stars.  From  his  measures,  compared  with 
Mildler's,  a  retrograde  movement  in  A  and  B  seems  to  be  certain. 

A  toB  Pos.  2710  00'     Dist.  =  0".G3    Epoch  1827. 16     Struve. 
264    35  0  .55  1841.80     Midler. 

A  -f-  B  to  C     Pos.  630  36     Dist.  22".25     Epoch  1827.16     Struve. 
2  60     18  22  .50  1841.80     Mudler. 

The  period  of  A  about  B,  is  probably  about  580  or  590  years. 

30  TAURI.— A.  R.  =  3  h.  39  m.  30  s.  Dec.  =  -}-  1 6°  38'  8".  A 
delicate  double  star  on  the  left  shoulder-blade  of  Taurus.  A  6,  "  pale 
emerald."  B  10,  "  purple." 

Discovered  by  Herschel. 

Pos.  58°  46'         Dist.  9".867        Epoch  1824.98     Struve. 

A  DOUBLE  STAR.— A.  R.  =  3  h.  51  m.  27  s.     Dec.  =  22°  44'  7". 

In  the  neck  of  Taurus,  between  the  Pleiades  and  Hyades.     A  7£,  B  8 
magnitude.     A  distant  companion  of  the  12  magnitude. 

Discovered  by  Struve. 

Pos.   127°  4 r         Dist  7". 208         Epoch  1823.98     South. 

80  TAURI.— A.  R.  =  4  h.21  m.Ol  s.  Dec.  =  -f-  15O  17'.  A 
close  double  star  on  the  Bull's  face,  1^°  south  west  of  Aldebaran.  A  6, 

B8$. 

Pos.  120  5f>'         Dist.  1".74        Epoch  1831.18     Struve. 

A  CLOSE  DOUBLE  STAR.— A.  R.  =  5  h.  7  m.  23  s.     Dec.  -f-  18° 
15'  3".     On  the  southern  horn  of  Taurus.     A  8,  B  8£. 
Discovered  by  Strive. 
Pos.  171°  13'         Dist.  2".327         Epoch  1830.53     Struve. 

A  DOUBLE  STAR.— A.  R.  =  5  h.  8  m.  03  s.     Dec.  =  -{-  19°  57'  2". 
In  the  middle  of  the  southern  horn  of  Taurus.     A  8,  B  11  magnitude. 
Discovered  by  Struve. 
Pos.  147°  33'         Dist.  10".547         Epoch  1828.19     Struve. 

118  TAURI.— A.  R.  =  5  h.  19  m.  25  s.  Dec.  =  -f.  25°  00'  8". 
Between  the  tips  of  the  Bull's  horns.  A  7,  B  74. 

Pos.  I960  46'         Dist.  4".89         Epoch  1829.63     Struve. 


CONSTELLATION   OF  TAURUS.  71 

A  LARGE  NEBULA.— A.  R.  =  5  h.  24  m.  51  s.  Decl.  =  -j-  21O  54' 
02".  One  degree  N.  W.  of  £  Tauri,  on  the  tip  of  the  Bull's  southern 
horn.  Discovered  by  Messier,  1758,  and  is  No.  1  of  his  great  catalogue. 
It  was  accidentally  picked  up  white  observing  the  comet  of  that  year,  and 
induced  Messier  to  commence  a  search  for  such  objects.  It  is  resolved 
with  difficulty  by  the  best  instruments,  and  Herschel  reckons  its  profun- 
dity of  the  980th  order — that  is,  980  times  more  remote  than  stars  of  the 
lirst  magnitude. 

H  TAURI.— A.  R.  =  3  h.  37  m.-  59  s.  Decl.  =  -f-  23O  36'  3".  Al- 
cyone, the  principal  star  in  the  Pleiades,  a  small  cluster  visible  to  the  eye 
in  the  neck  of  Taurus.  This  little  group  has  ever  been  remarkable,  but 
recently  a  tenfold  interest  has  been  given  to  it  by  the  announcement  of 
Dr.  Miidler  of  Dorpat,  Russia,  that  its  chief  star,  Alcyone,  is  the  central 
sun  of  our  astral  system.  It  is  absolutely  certain  that  the  law  of  gravi- 
tation extends  to  the  fixed  stars,  as  is  abundantly  shown  by  the  orbitual 
revolution  of  the  double  stars,  whose  periods  and  places  have  been  com- 
puted and  predicted  by  the  application  of  this  law. 

This  being  certain,  in  the  mighty  group  of  millions  of  stars  with  which 
our  own  sun  is  associated,  there  must  be  a  center  of  gravity  ,•  and  it 
then  remains  to  determine  whether  this  point  is  filled  by  a  ponderous 
globe,  of  vast  dimensions,  and  bearing  the  same  relation  in  point  of  mag- 
nitude to  the  millions  of  suns  by  which  it  is  surrounded,  as  our  sun  does 
to  the  planets,  satellites,  and  comets  by  which  it  is  encircled.  Analogy, 
in  the  solar  'system,  taught  the  existence  of  such  a  ponderous  mass,  but 
this  analogy  was  broken  in  the  revolving  stars ;  in  which  it  often  occurs 
that  the  components  are  nearly  equal  in  magnitude,  moving  round  a 
common  center  of  gravity. 

Again,  in  examining  the  heavens,  such  a  mighty  preponderating  body 
would  be  detected  by  the  swifter  proper  motion  of  the  stars  in  its  vicinity. 
After  a  laborious  search,  Miidler  reached  the  conclusion  that  no  such  vast 
globe  existed,  and  that  the  center  of  gravity,  probably  vacant,  could  only 
t>e  found  by  a  severe  examination  of  the  proper  motions  of  the  fixed  stars. 
By  a  beautiful  train  of  reasoning  and  closely  conducted  research,  he 
finally  reached  the  conclusion  that  Alcyone,  in  the  Pleiades,  now  holds 
the  high  rank  of  central  sun  ,•  but  that,  in  the  course  of  ages,  by  the 
perpetual  changes  constantly  going  on  among  the  components  of  our 
astral  system,  this  rank  may  pass  to  some  other  star.  He  computes 
roughly  the  distance  of  Alcyone,  and  reckons  it  to  be  so  great,  that  light, 
flying  with  a  velocity  of  twelve  millions  of  miles  a  minute,  cannot  reach 
us  from  that  star  hi  less  than  537  years.  He  further  computes  roughly, 
that  our  sun  revolves  about  Alcyone  in  a  period  of  18,200,000,  in  an 
orbit  inclined  to  the  ecliptic  under  an  angle  of  84°  00'.  Should  this 
wonderful  theory  be  confirmed,  the  proper  motions  of  the  fixed  stars 
assume  a  new  and  increased  interest — (See  Midler's  Paper,  "Central 
Sun" — Mitchel's  Sidereal  Messenger,  Nos.  4  and  5,  Vol.  I.) 

A  NEBULOUS  STAR. — A.  R.  =  3  h.  59  m.  06  s.  Decl.  -|-  30°  20 
05".  Over  the  neck  of  Taurus.  This  object  was  discovered  by  th« 
elder  Herschel,  and  was  the  final  link  in  that  long  chain  of  observation 


72         GEOGRAPHY  OF  THE  HEAVENS. 

which  led  to  the  adoption  of  the  «  nebular  theory."  The  star  is  perfectly 
in  the  center  of  the  nebulous  atmosphere  which  surrounds  it,  and  Her- 
schel  argues  the  nebulosity  of  this  seeming  atmosphere  from  the  fact  that, 
in  case  each  shining  point  is  a  star,  what  must  be  the  magnitude  of  the 
central  orb,  which  exceeds  them  all  in  the  enormous  ratio  of  millions  to 
one.  These  nebulous  stars  are  certainly  most  wonderful  objects,  and 
deserve  the  most  rigid  scrutiny. 

%  TATJHI A.  R.  ==  4h.  12  m.  51  s.     Decl.  =  -\-  25°  14'  07".    A 

double  star  at  the  back  of  the  Bull's  ear.     A  6,  B  8,  mag. 
Pos.  25QQO'         Dist.  19".3         Epoch  1831.91     Smyth. 


ORION. 

WHOEVER  looks  up  to  this  constellation  and  learns 
its  name,  will  never  forget  it.  It  is  too  beautifully 
splendid  to  need  a  description.  When  it  is  on  the 
meridian,  there  is  then  above  the  horizon  the  most 
magnificent  view  of  the  celestial  bodies  that  the 
starry  firmament  affords  ;  and  it  is  visible  to  all  the 
habitable  world,  because  the  equinoctial  passes 
through  the  middle  of  the  constellation.  It  is  rep- 
resented on  celestial  maps  by  the  figure  of  a  man 
in  the  attitude  of  assaulting  a  Bull,  with  a  sword  in 
his  belt,  a  huge  club  in  his  right  hand,  and  the  skin 
of  a  lion  in  his  left,  to  serve  for  a  shield. 

Manilius,  a  Latin  poet,  who  composed  five  books 
on  astronomy,  a  short  time  before  the  birth  of  our 
Saviour,  thus  describes  its  appearance  : 

"  First  next  the  Twins,  see  great  Orion  rise, 
His  arms  extended  stretch  o'er  half  the  skies ; 
His  stride  as  large,  and  with  a  steady  pace 
He  marches  on,  and  measures  a  vast  space; 
On  each  broad  shoulder  a  bright  star  display'd, 
And  three  obliquely  grace  his  hanging  blade. 
In  his  vast  head,  immers'd  in  boundless  spheres, 
Three  stars,  less  bright,  but  yet  as  great,  he  bears, 
But  farther  off  removed,  their  splendor's  lost ; 
Thus  grac'd  and  arm'd,  he  leads  the  starry  host. " 

The  center  of  the  constellation  is  midway  between 
the  poles  of  the  heavens  and  directly  over  the  equa- 


CONSTELLATION  OF  ORION.  73 

tor.  It  is  also  about  8°  W.  of  the  solstitial  colure, 
and  comes  to  the  meridian  about  the  23d  of  Janu- 
ary. The  whole  number  of  visible  stars  in  this 
constellation  is  seventy-eight ;  of  which  two  are 
of  the  1st  magnitude,  four  of  the  2d,  three  of  the 
3d,  and  fifteen  of  the  4th. 

Those  four  brilliant  stars  in  the  form  of  a  long 
square  or  parallelogram,  intersected  in  the  middle 
by  the  "  Three  Stars,"  or  "  Ell  and  Yard,"  about 
25°  S.  of  the  Bull's  horns,  form  the  outline  of  Orion. 
The  two  upper  stars  in  the  parallelogram  are  about 
15°  N.  of  the  two  lower  ones  ;  and,  being  placed 
on  each  shoulder,  may  be  called  the  epaulets  of 
Orion.  The  brightest  of  the  two  lower  ones  is  in 
the  left  foot,  on  the  W.,  and  the  other,  which  is  the 
least  brilliant  of  the  four,  in  the  right  knee.  To  be 
more  particular  :  Bellatrix,  y  Orionis,  is  a  star  of  the 
2d  magnitude  on  the  W.  shoulder ;  Betelguese,  a 
Orionis,  is  a  star  of  the  1st  magnitude,  ?i°  E.  of 
Bellatrix,  on  the  E.  shoulder.  It  is  brighter  than 
Bellatrix,  and  lies  a  little  farther  towards  the  north  ; 
and  comes  to  the  meridian  thirty  minutes  after  it, 
on  the  21&t  of  January.  These  two  form  the  upper 
end  of  the  parallelogram. 

Rigel,  /3  Orionis,  is  a  splendid  star  of  the  1st  mag- 
nitude, in  the  left  foot,  on  the  W.  and  15°  S.  of 
Bellatrix.  Saiph,  is  a  star  of  the  3d  magnitude,  in 
the  end  of  the  sword  scabbard,  8^°  E.  of  Rigel. 
These  two  form  the  lower  end  of  the  parallelogram. 


First  in  rank 


The  martial  star  upon  his  shoulder  flames : 
A  rival  star  illuminates  his  foot ; 
And  on  his  girdle  beams  a  luminary 
Which,  in  vicinity  of  other  stars, 
Might  claim  the  proudest  honors." 

There  is  a  little  triangle  of  three  small  stars  in 
the  head  of  Orion,  which  forms  a  larger  triangle 
with  the  two  in  his  shoulders.     In  the  middle  of  the 
G 


74         GEOGRAPHY  OF  THE  HEAVENS. 

parallelogram  are  three  stars  of  the  2d  magnitude, 
in  the  belt  of  Orion,  that  form  a  straight  line  about 
3°  in  length  from  N.  W.  to  S.  E.  They  are  usually 
distinguished  by  the  name  of  the  Three  Stars,  be- 
cause there  are  no  other  stars  in  the  heavens  that 
exactly  resemble  them  in  position  and  brightness. 
They  are  sometimes  denominated  the  Three  Kings, 
because  they  point  out  the  Hyades  and  Pleiades  on 
one  side,  and  Sirius,  or  the  Dog-star  on  the  other. 
In  Job  they  are  called  the  Bands  of  Orion;  while 
the  ancient  husbandmen  called  them  Jacob's  rod,  and 
some  times  the  Rake.  The  University  of  Leipsic,  in 
1807.  gave  them  the  name  of  Napoleon.  But  the 
more  common  appellation  for  them,  including  those 
in  the  sword,  is  the  Ell  and  Yard.  They  derive  the 
latter  name  from  the  circumstance  that  the  line 
which  unites  the  "  three  stars  "  in  the  belt  measures 
just  3°  in  length,  and  is  divided  by  the  central  star 
into  two  equal  parts,  like  a  yard-stick  ;  thus  serving 
as  a  graduated  standard  for  measuring  the  distances 
of  stars  from  each  other.  When  therefore  any  star 
is  described  as  being  so  many  degrees  from  another, 
in  order  to  determine  the  distance,  it  is  recommend- 
ed to  apply  this  rule. 

It  is  necessary  that  the  scholar  should  task  his  ingenuity  only  a  few 
evenings  in  applying  such  a  standard  to  the  stars,  before  he  will  learn  to 
judge  of  their  relative  distances  with  an  accuracy  that  will  seldom  vary 
a  "degree  from  the  truth. 

The  northernmost  star  in  the  belt,  called  Mintika, 
a,  is  less  than  J°  S.  of  the  equinoctial,  and  when  on 
the  meridian,  is  almost  exactly  over  the  equator. 
It  is  on  the  meridian,  the  24th  of  January. 

The  "  three  stars  "  are  situated  about  8°  W.  of 
the  solstitial  colure,  and  uniformly  pass  the  meridian 
one  hour  and  fifty  minutes  after  the  seven  stars. 

There  is  a  row  of  stars  of  the  4th  and  5th  mag- 
nitudes, S.  of  the  belt,  running  down  obliquely  to- 
wards Saiph,  which  forms  the  sword.  This  row  is 


CONSTELLATION  OF  ORION.  75 

also  called  the  Ell,  because  it  is  once  and  a  quarter 
the  length  of  the  Yard  or  belt. 

A  very  little  way  below  Thabit,  »  Orionis,  in  the 
sword,  there  is  a  nebulous  appearance,  the  most 
remarkable  one  in  the  heavens.  With  a  good  tele- 
scope an  apparent  opening  is  discovered,  through 
which,  as  through  a  window>  we  seem  to  get  a 
glimpse  of  other  heavens,  and  brighter  regions 
beyond. 

As  the  telescope  extends  our  knowledge  of  the  stars  and  greatly  in- 
creases their  visible  number,  we  behold  hundreds  and  thousands,  which, 
but  for  this  almost  divine  improvement  of  our  vision,  had  forever  remain- 
ed, unseen  by  us,  in  an  unfathomable  void. 

A  star  in  Orion's  sword,  which  appears  single  to  the  unassisted  vision, 
is  multiplied  into  six  by  the  telescope ;  and  another  into  twelve.  Galileo 
found  eighty  in  the  belt,  twenty-one  in  a  nebulous  star  in  the  head,  and 
about  five  hundred  in  another  part  of  Orion,  within  the  compass  of  one 
or  two  degrees.  Dr.  Hook  saw  seventy-eight  stars  in  the  Pleiades,  and 
Rheita  with  a  better  telescope,  saw  about  two  hundred  in  the  same  cluster 
and  more  than  two  thousand  in  Orion. 

About  9°  W.  of  Bellatrix,  y,  are  eight  stars,  chiefly 
of  the  4th  magnitude,  in  a  curved  line  running  N. 
and  S.  with  the  concavity  towards  Orion ;  these 
point  out  the  skin  of  the  lion  in  his  left  hand.  Of 
Orion,  on  the  whole,  we  may  remark  with  Eudosia: 

"  He  who  admires  not,  to  the  stars  is  blind."' 

As  the  constellation  Orion,  which  rises  at  noon  about  the  9th  day  of 
March,  and  sets  at  noon  about  the  21st  of  June,  is  generally  supposed  to 
be  accompanied,  at  its  rising,  with  great  rains  and  storms,  it  became  ex- 
tremely terrible  to  mariners,  in  the  early  adventures  of  navigation.  Virgil, 
Ovid,  and  Horace,  with  some  of  the  Greek  poets,  make  mention  of  this. 

Thus  Eneas  accounts  for  the  storm  which  cast  him  on  the  African 
coast  on  his  way  to  Italy  : — 

"  To  that  blest  shore  we  steer'd  our  destined  way, 
When  sudden,  dire  Orion  rous'd  the  sea  : 
All  charg'd  with  tempests  rose  the  baleful  star, 
And  on  our  navy  pour'd  his  wat'ry  war." 

To  induce  him  to  delay  his  departure,  Dido's  sister  advises  her  to 

"  Tell  him,  that,  charg'd  with  deluges  of  rain, 
Orion  rages  on  the  wintry  main." 


76  GEOGRAPHY  OF  THE  HEAVENS. 

The  name  of  this  constellation  is  mentioned  in  the  books  of  Job  and 
Amos,  and  in  Homer.  The  inspired  prophet,  penetrated  like  the  psalmist 
of  Israel,  with  the  omniscience  and  power  displayed  in  the  celestial  glories, 
utters  this  sublime  injunction  :  "  Seek  Him  that  maketh  the  seven  stars 
and  Orion,  and  turneth  the  shadow  of  death  into  morning."  Job  also, 
with  profound  veneration,  adores  His  awfol  majesty  who  "  commandeth  the 
sun  and  sealeth  up  the  stars ;  who  alone  spreadeth  out  the  heavens,  and 
maketh  Arcturus,  Orion,  and  Pleiades,  and  the  chambers  of  the  south  :  " 
And  in  another  place,  the  Almighty  demands  of  him — •'  Knowest  thou 
the  ordinances  of  heaven  1  Canst  thou  bind  the  sweet  influences  of  the 
Pleiades,  or  loose  the  bands  of  Orion  ;  canst  thou  bring  forth  Mazzaroth. 
in  his  season,  or  canst  thou  guide  Arcturus  with  his  sons  1  " 

Calmet  supposes  that  Mazzaroth  is  here  put  for  the  whole  order  of 
celestial  bodies  in  the  Zodiac,  which  by  their  appointed  revolutions,  pro- 
duce the  various  seasons  of  the  year,  and  the  regular  succession  of  day  and 
night.  Arcturus  is  the  name  of  the  principal  star  in  Bootes,  and  is 
here  put  for  the  constellation  itself.  The  expression,  his  sons,  doubtless 
refers  to  Asterion  and  Chara,  the  two  greyhounds,  with  which  he  seems 
to  be  pursuing  the  great  bear  around  the  .North  pole. 

TELESCOPIC    OBJECTS. 

258  P.  IV.  ORTOXTS.— A.  R.  =  4  h.  49m.  48s.     Dec.  =  4-   1° 
25'  04".     A  double  star  preceding  Orion's  right  knee.     A  8£,  B  9,  mag. 
Discovered  by  Herschel. 

Pos.  1740  51'         Dist.  2".00         Epoch  1782.85     Herschel. 
179     54  2  .64  1832.09     Striive. 

£  ORIONIS.— A.  R.  =  5  h.  04  m.  55  s.  Dec.  =  -|-  2°  39'  09".  A 
double  star  between  the  right  arm  and  thigh  of  Orion.  A  5,  B  8£,  the 
first  orange,  the  second  blue. 

Pos.  63°  28'         Dist.  7".  05         Epoch  1832.05     Striive. 

£  ORIOSIS.— A.  R.  =  5  h.  6  m.  51  s.  Dec.  =  —  8O  23'  05".  Ri- 
gel,  a  double  star  in  the  right  foot  of  Orion.  A  1 ,  "  pale  yellow,"  B  9, 
"  sapphire  blue."  A  third  star  has  been  recently  added  by  artificial 
occultation,  at  the  Cincinnati  Observatory.  It  is  of  the  20th  magnitude, 
and  invisible  without  hiding  the  principal  stars. 

The  relative  positions  of  the  stars  remain  unchanged  since  their  dis- 
covery, in  1781. 

Discovered  by  Herschel. 

Pos.  199°  46'         Dist.  9".14        Epoch  1831.53     Struve. 

84  P.  V.  ORIOKIS.— A.  R,  =  5  h.  16  m.  53  s.  Dec.  =  -f-  1°  46'  4". 
A  close  double  star  hi  Orion's  right  side.  A  8,  B  10.  The  components 
are  fixed. 

Discovered  by  Herschel. 

Pos.  323°  13'         Dist  2".61         Epoch  1831.81. 

32  ORIOXIS.— A.  R.  =  5  h.  22  m.  13  s:  Dec  =  -f-  5O  49'  03".  A 
close  double  star  on  the  right  shoulder  of  Orion.  A  5,  B  7,  mag.  A 


CONSTELLATION    OF  ORION.  77 

parison  of  late  measures  with  those  of  Herschel  in  1780,  indicates  a  slow 
retrograde  motion,  amounting  to  some  10°  or  12°  in  half  a  century. 
Pos.  203°  45'         Dist.  1".04         Epoch  1830.96     Strive. 

33  ORIOX  rs.— A.  R.  =  5  h  22  m,  5 1  s.     Dec.  =  -f-  3°  09'  9".     A 
close  double  star  on  the  right  shoulder.     A  6,  B  8,  mag. 
Pos.  25°  35'         Dist.  1".87         Epoch  1831.22     Struve. 

x  ORIOX.S.— A.  R.  =  5  h.  26  m.  19  s.  Dec.  =  -f  9°  49'  03".  A 
double  star  in  the  ear  of  Orion.  A  4,w"  pale  white,"  B  6,  violet.  No 
change  has  been  detected. 

Discovered  by  Herschel,  1779. 

Pos.  40°  32'         Dist.  4".24         Epoch  1830.21     Struve. 

Q  OHIO* is.— A.  R.  =  5  h.  27  m.  25  s.  Dec.— 5°  30'.  A  sextuple 
star  in  the  great  nebula  in  the  sword  scabbard  of  Orion.  A  6,  B  7, 
C  7£,  D  8,  E  15,  F  16,  mag.  For  more  than  fifty  years  this  object  was 
regarded  as  only  quadruple.  After  the  mounting  of  the  "  Dorpat  refrac- 
tor," Strive  added  a  fifth  star  to  the  four  already  known ;  and  a  few 
years  since  a  sixth  was  discovered  by  Sir  James  South. 

It  is  not  certain  that  any  change  has  yet  been  detected  among  the 
components  of  this  remarkable  grpup. 

Pos.  A  B,  3110  14'         Dist,  12".983         Epoch  1832.53     Struve. 
A  C,     60     07  13  .467  1832.53         « 

A  D,  342     10  16  .780  1832.53         « 

B  E,  355    42  3  .860  1832.53        « 

THE  GREAT  NEBULA  iv  OHIOX. — A.  R.  =  5h.  27  m.  25  s.  Dec. 
=  —  5°  30'.  This  stupendous  object  is  situated  in  the  middle  of  the 
scabbard  of  Orion's  sword.  Discovered  by  Huygens,  1656.  It  has  been 
an  object  of  the  greatest  interest,  to  all  astronomers,  in  consequence  of  its 
brilliancy  and  extraordinary  magnitude.  Sir  William  Herschel  repeat- 
edly examined  it  with  scrutiny  with  his  forty  feet  refractor,  but  detected 
nothing  like  resolvability.  Most  accurate  drawings  were  made  by  his 
son,  without  any  suspicion  that  it  was  composed  of  a  mass  of  stars.  As 
Sir  John  Herschel  remarked,  the  greater  the  power  employed  the  more 
mysterious  did  the  object  appear.  Dr.  J.  Lamont,  of  Munich,  has  exa- 
mined this  nebula  with  great  attention,  and  many  years  since  affirmed 
that  with  the  twelve  inch  refractor  of  the  Munich  Observatory,  he  caught 
glimpses  of  multitudes  of  point-like  stars,  crowding  and  producing  the 
brighter  parts  of  the  nebula ;  yet  to  this  announcement  little  heed  seems 
to  have  been  given.  On  mounting  the  giant  reflector  of  Lord  Rosse,  it 
was  a  matter  of  deep  interest  to  learn  the  appearance  of  this  nebula  under 
the  scrutiny  of  this  magnificent  instrument.  More  than  one  astronomer 
made  the  journey  to  the  castle  of  Lord  Rosse,  to  inspect  this  wonderful 
object.  For  a  long  time  it  resisted  the  full  power  of  the  greatest  of  all 
optical  instruments,  until  at  length  Lord  Rosse  makes  the  following  an- 
nouncement : 

"  Castle  Parsantown,  March  19,  1846. 

"  In  accordance  with  my  promise  of  communicating  to  you  the  result 
of  our  examination  of  Orion,  I  think  I  can  safely  say  there  can  be  but 


78  GEOGRAPHY   OF  THE   HEAVENS. 

little,  if  any  doubt,  as  to  the  resolvability  of  the  nebula.  Since  you  left 
us,  there  was  not  a  single  night,  when,  in  absence  of  the  moon,  the  air 
was  free  enough  to  admit  the  use  of  more  than  half  the  magnifying 
power  the  speculum  bears ;  still,  we  could  plainly  see,  that  all  about  the 
trapezium  is  a  mass  of  stars  ;  the  rest  of  the  nebula  abounding  in  stars, 
and  exhibiting  the  characteristics  of  resolvability  strongly  marked. 

"  ROSSE." 

This  announcement  has  been  made  the  basis  of  an  argument,  by  Dr. 
Nichol,  to  overthrow  the  nebular  theory  of  the  formation  of  the  universe ; 
a  theory  which  had  derived  much  of  its  popularity  from  the  powerful 
argument  in  its  behalf  made  by  the  same  gentleman,  a  short  time  before, 
iu  his  "  Architecture  of  the  Heavens."  If  Lord  Rosse  is  quite  sure  of 
the  resolution  of  the  nebula,  it  but  confirms  the  previous  declaration  of 
Dr.  Lamont,  and  the  nebular  theory  loses  but  little  of  its  former  strength 
by  the  removal  of  a  prop  already  much  shaken  by  the  Munich  Astronomer. 
Resolved  or  unresolved,  this  is  certainly,  under  every  aspect,  one  of  the 
most  sublime  objects  revealed  by  telescopic  agency — so  vast  that  the 
mind  fails,  utterly,  to  grasp  its  mighty  outlines.  A  s  a  starry  system,  it  is 
so  distant  that  the  light  which  leaves  it,  to  journey  to  our  eyes,  spends 
no  less  than  30,000  years  in  sweeping  over  the  stupendous  interval.  As 
a  nebula,  it  contains  materials  sufficient  for  the  production  of  millions  of 
suns  and  systems.  View  it  as  we  may,  its  vastness,  its  magnificence,  must 
exalt  our  ideas  of  the  omnipotence  of  the  Great  Architect  of  the  Heavens. 
Under  the  full  power  of  the  Cincinnati  refractor,  the  deep  contrast  be- 
tween the  brilliancy  of  the  stars  and  nebulosity,  and  the  jet  black  heavens 
on  which  they  are  seen,  is  one  of  the  most  beautiful  sights  in  the  heavens. 
Whether  this  blackness  be  the  effect  of  mere  contrast,  or  an  intrinsic 
darkness,  occasioned  by  the  absence  of  all  light,  it  is  difficult  to  determine. 
This  is  not  a  solitary  instance  of  the  phenomenon  in  question.  I  have  ob- 
served the  same  in  several  other  instances — but  in  no  case  have  I  remark- 
ed such  intense  blackness  in  the  heavens,  as  about  this  nebula. 


a-  Oiuoyis.—  A.  R.  =  5  h.  30  m.  43  s.  Dec,  =  —  2°  41'  8".  A 
multiple  star  just  below  the  belt  of  Orion,  an  excellent  object  for  testing 
the  light  of  telescopes.  There  are  no  less  than  ten  stars  counted  as  the 
components  of  this  one.  A  4,  a  U,  B  8,  C  7,  D  8|,  E  9,  F  8, 
magnitudes. 

34  HEHSCHEI,  ORIONIS. — A.  R.  =  5  h,  33  m.  21  s.  Dec.  =  -f- 
9°  00'  2".  A  planetary  nebula  on  Orion's  neck. 

Discovered  by  Herschel,  and  described  by  his  son  as  "  a  small  pale, 
but  distinct  nebula,  with  a  faint  disc,  rather  oval,  and  perhaps  a  little 
mottled." 

78  MKSSIER,  ORIONIS.— A.  R.  =  5  h.  38  m.  33  s.  Dec.  =  -f  0° 
00'  7".  "  Two  stars  in  a  wispy  nebula,  just  above  Orion's  hip."  This 
is  a  remarkable  object. 

Discovered  by  Messier  in  1780. 


CONSTELLATION  OF  ORION.  79 

52  ORIOXIS.— A.  R.  =  5  h,  39  m  24  s.  Dec.  =  -f-  6°  23'  6".  A 
close  double  star  in  Orion's  left  shoulder.  A  6,  B  6£  magnitude.  The 
position  has  never  changed. 

Pos.  200°  01          Dist.   1".75         Epoch  1831.23     Struve. 


E  RID AN  US  . 

THE  RIVER  Po. — This  constellation  meanders  over 
a  large  and  very  irregular  space  in  the  heavens.  It 
is  not  easy,  nor  scarcely  desirable,  to  trace  out  all 
its  windings  among  the  stars.  Its  entire  length  is 
not  less  than  130°;  which,  for  the  sake  of  a  more 
easy  reference,  astronomers  divide  into  two  sections, 
the  northern  and  the  southern.  That  part  of  it  which 
lies  between  Orion  and  the  Whale,  including  the 
great  bend  about  his  paws,  is  distinguished  by  the 
name  of  the  Northern  stream  ;  the  remainder  of  it 
is  called  the  Southern  stream. 

The  Northern  stream  commences  near  Rigel 
(Map  No.  V),  in  the  foot  of  Orion,  and  flows  out 
westerly,  in  a  serpentine  course  nearly  40°,  to  the 
Whale  (Map  No.  IV),  where  it  suddenly  makes  a 
complete  circuit  and  returns  back  nearly  the  same 
distance  towards  its  source,  but  bending  gradually 
down  towards  the  south,  when  it  again  makes  a 
similar  circuit  to  the  S.  W.  and  finally  disappears 
below  the  horizon. 

West  of  /3  Orionis  (Map  No  V)  there  are  five  or  six  stars  of  the  3d  and 
4th  magnitudes,  arching  up  in  a  semicircular  form,  and  marking  the  first 
bend  of  the  northern  stream.  About  8°  below  these,  or  19°  W.  of  @>, 
is  a  bright  star  of  the  2d  magnitude,  in  the  second  bend  of  the  northern 
stream,  marked  y.  This  star  culminates  thirteen  minutes  after  the 
Pleiades,  and  one  hour  and  a  quarter  before  $.  Passing  y,  and  a  smaller 
star  west  of  it,  there  are  four  stars  nearly  in  a  row,  which  bring  us  to  the 
breast  of  Cetus.  8°  N.  of  y,  is  a  small  star  named  Kied,  which  is  thought 
by  some  to  be  considerably  nearer  the  earth  than  Sirius. 

Theemim,  in  the  southern  stream,  is  a  star  of  the  3d  magnitude,  about 
17-  S.  W.  of  the  square  in  Lepus,  and  may  be  known  by  means  of  a 
smaller  star.  1°  above  it.  Achernar  is  a  brilliant  star  of  the  1  st  magnitude, 
in  the  extremity  of  the  southern  stream ;  but  having  58°  of  S.  declina- 
tion, can  never  be  seen  in  this  latitude. 


80          GEOGRAPHY  OF  THE  HEAVENS. 

The  whole  number  of  stars  in  this  constellation  is 
eighty-four;  of  which,  one  is  of  the  1st  magnitude, 
one  of  the  2d,  and  eleven  are  of  the  3d.  Many  of 
these  cannot  be  pointed  out  by  verbal  description  ; 
they  must  be  traced  from  the  map. 

TELESCOPIC    OBJECTS. 

98,  P,  IE,  ERIDANI.— A.  R.  =  3  h.  28  m.  35  s.  Dec.  =  -j-  0° 
03'  7".  A  delicate  double  star,  in  the  line  joining  a.  Ceti  and  $  Orionis, 
at  one-third  their  distance.  A  6£,  yellow  ;  B  9,  pale  blue. 

Discovered  by  Herschel. 

Pos.  225°  12'         Dist.  5". 812         Epoch   1824.02     Struve. 

This  object  is  between  the  Bull's  chest  and  the  northern  branch  of  the 
River. 

107  HERSCHEL  I,  ERIDAWT. — A.  R.  =  3  h.  33  m.  02  s.     Dec.  = 

—  19°  04'  8".     A  white  nebula  between  the  two  northern  reaches  of 
the  River. 

Discovered  by  Herschel,  and  described  as  "  pale  but  distinct,  round  and 
bright  in  the  center." 

32  ERIDANI.— A.  R.  =  3  h.  46  m.  16  s.  Dec.  =  —  3°  25'  9".  A 
double  star  between  the  chest  of  Taurus  and  the  River.  A  5,  yellow  ; 
B  7,  sea  green. 

Discovered  by  Herschel. 

Pos.  3490  45'         Dist.  6".75         Epoch  1825.00     Struve. 

39  ERIDAXI.— A.  R.  =  4  h.  06  m.  48  s.  Dec.  —  10°  39'  4".  A 
double  star  in  the  north,  following  bend  of  the  River.  A  5,  "  full  yellow ; " 
B  11,  "deep  blue.'* 

Discovered  by  Herschel. 

Pos.  1520  12'         Dist.  6".28         Epoch  1833.14     Struve. 

26  HERSCHEL  IV,  ERIDANI.— A.  R.  =  4  h.  06  m.  50  s.     Dec,  = 

—  13°  09'  1"     A  planetary  nebula  under  the  N.  F.  bend  of  the  River. 
Discovered  by  Herschel,  in  1784,  who  saw  it  slightly  elliptical,  and 

thought  it  might  be  a  globular  cluster  at  an  immense  distance. 


CONSTELLATION   OF  AURIGA.  81 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    VI. 

AURIGA — THE  WAGONER. 

Favorably  situated  for  examination  in  December, 
January,  February  and  March. 

AURIGA. 

THE  Charioteer,  called  also  the  Wagoner,  is  rep- 
resented on  the  celestial  map  by  the  figure  of  a  man 
in  a  reclining  posture,  resting  one  knee  upon  the 
horn  of  Taurus,  with  a  goat  and  her  kids  in  his 
right  hand,  and  a  bridle  in  his  left. 

It  is  situated  N.  of  Taurus  and  Orion,  between 
Perseus  on  the  W.  and  the  Lynx  on  the  E.  Its 
mean  declination  is  45°  N. ;  so  that  when  on  the 
meridian,  it  is  almost  directly  ove'r  head  in  New 
England.  It  is  on  the  same  meridian  with  Orion, 
and  culminates  at  the  same  hour  of  the  night. 
Both  of  these  constellations  are  on  the  meridian  at 
9  o'clock  on  the  24th  of  January,  and  1  hour  and  40 
minutes  east  of  it  on  the  1st  of  January. 

The  whole  number  of  visible  stars  in  Auriga  is 
sixty-six,  including  one  of  the  1st  and  one  of  the  2d 
magnitude,  which  mark  the  shoulders.  Capella,  a 
Aurigse,  is  the  principal  star  in  this  constellation, 
and  is  one  of  the  most  brilliant  in  the  heavens.  It 
takes  its  name  from  Capella,  the  goat,  which  hangs 
upon  the  left  shoulder.  It  is  situated  in  the  west 
shoulder  of  Auriga,  24°  E.  of  Algol,  and  28°  N.  E. 
of  the  Pleiades.  It  may  be  known  by  a  little  shai-p- 
pointed  triangle  formed  by  three  stars,  3°  or  4°  this 
side  of  it,  on  the  left.  It  is  also  18°  N.  of  p  Tauri, 
which  is  common  to  the  northern  horn  of  Taurus, 
and  the  right  foot  of  Auriga.  Capella  conies  to  the 
meridian  on  the  19th  of  January,  just  2^  minutes 


82         GEOGRAPHY  OF  THE  HEAVENS, 

before  j3,  in  the  foot  of  Orion,  which  it  very  much 
resembles  in  brightness. 

Menkalina,  $  Aurigse,  in  the  east  shoulder,  is  a  star  of  the  2d  magni- 
tude, 7£°  E.  of  Capella,  and  culminates  the  next  minute  after  Betelguese, 
A  Orionis,  3?3°  S.  of  it.  6,  in  the  right  leg,  is  a  star  of  the  4th 
magnitude,  8°  directly  south  of  Menkalina, 

It  may  be  remarked  as  a  curious  coincidence,  that  the  two  stars  in  the 
shoulders  of  Auriga  are  of  the  same  magnitude,  and  just  as  far  apart  as 
those  in  Orion,  and  opposite  to  them.  Again,  the  two  stars  in  the  shoul- 
ders of  Auriga,  with  the  two  in  the  shoulders  of  Orion,  mark  the  ex- 
tremities of  a  long,  narrow  parallelogram,  lying  N.  and  S.,  and  whose 
length  is  just  five  times  its  breadth.  Also,  the  two  stars  in  Auriga,  and 
the  two  hi  Orion,  make  two  slender  and  similar  triangles,  both  meeting 
in  a  common  point,  half  way  between  them,  at  /g,  in  the  northern  horn 
of  Taurus. 

Delta,  a  star  of  the  4th  magnitude  in  the  head  of  Auriga,  is  about  9° 
N.  of  the  two  in  the  shoulders,  with  which  it  makes  a  triangle,  about  half 
the  hight  of  those  just  alluded  to,  with  the  vertex  at  Delta.  The  two 
stars  in  the  shoulders  are  therefore  the  base  of  two  similar  triangles,  one 
extending  about  9°  N.,  to  the  head,  the  other  18°  S.,  to  the  heel,  on  the  top 
of  the  horn :  both  figures  together  resembling  an  elongated  diamond. 

Delta  in  the  head,  /3  in  the  right  shoulder,  and  6  in  the  arm  of  Auriga, 
make  a  straight  line  with  Betelguese  hi  Orion,  J*  in  the  square  of  the 
Hare,  and  /3  hi  Noah's  Dove ;  all  being  very  nearly  on  the  same  meridian, 
40  W.  of  the  solstitial  colure. 

"  See  next  the  Goatherd  with  his  kids ;  he  shines 
With  seventy  stars,  deducting  only  four, 
Of  which  Capella  never  sets  to  us, 
And  scarce  a  star  with  equal  radiance  beams 
Upon  the  earth :  two  other  stars  are  seen 
Due  to  the  second  order." — Eudosia. 

TELESCOPIC   OBJECTS. 

u  AURIGJB.— A.  R.  =  4  h.  48  m.  24  s.  Dec.  =  -f  37°  38'  5".  A 
double  star  preceding  the  hip  of  Auriga.  A  5.  pale  red ;  B  9,  light  blue. 

Discovered  by  Sir  W.  Herschel,  who  records  the  following  measures. 

Pos.  =  352°  37'         Dist.  =  5".  50         Epoch  1779.85 

351    56  6  .46  18i8.75     Striive. 

Though  the  distances  recorded  by  Herschel  differ  from  the  later  ones, 
there  is  no  reason  to  believe  that  the  difference  is  due  to  an  actual 
change  in  the  places  of  these  two  stars.  Herschel's  means  of  making 
measures  were  less  perfect  than  those  now  hi  use  ;  and  his  measures  are 
less  to  be  relied  on,  from  this  cause. 

5  AVRIOJE. — A  little  north,  and  following  a>  Aurigse.  A  delicate 
double  star.  A  6,  B  10  magnitude. 

Discovered  by  Striive,  with  the  Polkova  refractor. 


CONSTELLATION  OF  AURIGA.  83 

A  CLOSE  DOUBLE  STAR. — A.  R.  =  4  h.  57  m.  11  s.  Dec.  =  -\- 
37°  08'  4".  On  the  lower  garment  of  Auriga.  A  7,  B  8  magnitude, 
near  a  loose  cluster. 

Discovered,  by  Strive,  whose  measures  stood  as  follows  : 
Pos.  219°  12'         Dist.  =  1'<.61         Epoch  1828.60 

14  AuniGas.— A.  R.  =  5  h.  04  m.  59  s.  Dec.  =  -j-  32°  29' 8".  A 
triple  star  in  the  right  knee  of  Auriga.  A  5,  B  7|,  C  16  magnitude. 
A  and  B  have  been  long  known,  C  was  recently  added  by  Prof.  Striive. 
He  records  these  measures. 

AB  Pos.  225048'         Dist.  14".  653         Epoch  1830.55 
AC  342    37  12  .577  1830.55 

A  CLUSTER.— A.  R.  =  5  h.  17  m.  18  s.  Dec.  =  -{-  35°  10'  3". 
On  the  robe  under  the  left  thigh  of  Auriga.  This  object  is  about  3'  in 
diameter,  and  is  composed  of  stars  of  various  magnitudes,  from  the  10th 
to  the  14th.  It  is  preceded  by  a  small  double  star.  A  9^,  B  1 1  magni- 
tude. Dist.  5".00 

Discovered  by  Herschel.  1787. 

A  RICH  CLUSTER — A.  R.  =  5  h.  18  m.  41  s.  Dec.  =  -f-  35°  44' 
9".  Dn  the  left  thigh  of  Auriga. 

Discovered  by  Messier,  1764,  and  described  by  him  as  "  a  mass  of  stars 
of  a  square  form,  without  any  nebulosity,  extending  to  about  15'  of  one 
degree." 

A  RESOLVABLE  NKBULA. — A.  R  =  5  h.  20  m.  51  s.  Dec.  =  -f- 
34°  06'  9".  On  the  lower  garment  of  Auriga. 

Discovered  by  Herschel  in  1793,  who  says  that  it  seems  to  have  one 
or  two  stars  in  the  middle,  or  an  irregular  nucleus. 

A  FINE  CLUSTER.— A.  R.  =  5  h.  41  m.  46  s.  Dec.  =-{-  32°  30' 
1".  In  front  of  Auriga's  left  shin. 

Discovered  by  Messier,  1764,  and  described  as  "a  mass  of  small  stars 
in  nebulous  matter." 

6  AURIGA.— A.  R.  =  5  h.  48m.  48  s.     Dec.  -f-  37O  11' 7".     A 
fine  double  star  in  the  left  wrist.     A  4,  lilac ;  B  1 0,  pale  yellow. 
'     Pos.  28900'         Dist.  30".00         Epoch   1832.64 

41  AuniojE.— A.  R.  =  5  h.  59  m.  21  s.  Dec.  =  -f-  48°  44'  1". 
On  the  chin  of  Auriga.  A  7,  white ;  B  7£,  violet. 

Pos.  3530  07'         Dist.  7".99         Epoch  1830.31     Struve. 

Many  other  double  and  triple  stars,  nebulse  and  clusters,  may  be  found 
on  the  charts,  and  by  alignment  their  places  in  the  heavens  may  be 
readily  made  out. 


CONSTELLATION  OF  GEMINI.  85 


CHAPTER  II. 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    VII. 

GEMINI — THE  TWINS. 
CANCER — THE  CRAB. 
CANIS  MINOR — THE  LITTLE  DOG. 
Favorably  situated  for  examination  in  January,  Febru- 
ary',  March  and  April. 

GEMINI. 

THE  TWINS. — This  constellation  represents  the 
twin  brothers,  Castor  and  Pollux. 

Gemini  is  the  third  sign,  but  fourth  constellation  in 
the  order  of  the  Zodiac,  and  is  situated  south  of  the 
Lynx,  between  Cancer  on  the  east  and  Taurus  on 
the  west.  The  orbit  of  the  earth  passes  through 
the  center  of  the  constellation.  As  the  earth  moves 
round  in  her  orbit  from  the  first  point  of  Aries  to  the 
same  point  again,  the  sun,  in  the  meantime,  will 
appear  to  move  through  the  opposite  signs,  or  those 
which  are  situated  right  over  against  the  earth,  on 
the  other  side  of  her  orbit. 

Accordingly,  if  we  could  see  the  stars  as  the  sun 
appeared  to  move  by  them,  we  should  see  it  passing 
over  the  constellation  Gemini  between  the  21st  of 
June  and  the  23d  of  July  ;  but  we  seldom  see  more 
than  a  small  part  of  any  constellation  through  which 
the  sun  is  then  passing,  because  the  feeble  luster 
of  the  stars  is  obscured  by  the  superior  effulgence 
of  the  sun. 

When  the  sun  is  just  entering  the  outlines  of  a  constellation  on  the 

H 


80         GEOGRAPHY  OF  THE  HEAVENS. 

east,  its  wester  limits  may  be  seen  in  the  morning  twilight,  just  above 
the  rising  sun.  So  when  the  sun  has  arrived  at  the  western  limit  of  a 
constellation,  the  eastern  part  of  it  may  be  seen  lingering  in  the  evening 
twilight,  just  behind  the  setting  sun.  Under  other  circumstances,  when 
the  sun  is  said  to  be  in,  or  to  enter,  a  particular  constellation,  it  is  to 
be  understood  that  the  constellation  is  not  then  visible,  but  that  those 
opposite  to  it,  are.  For  example  :  whatever  constellation  sets  with  the 
sun  on  any  day.  it  is  plain  that  the  one  opposite  to  it  must  be  then  rising, 
and  continue  visible  throughout  the  night.  Also,  whatever  constellation 
rises  and  sets  with  the  sun  to-day,  will,  six  months  hence,  rise  at  sun- 
setting,  and  set  at  sun-rising.  For  example :  the  sun  is  in  the  center  of 
Gemini  about  the  6th  of  July,  and  must  rise  and  set  with  it  on  that  day  ; 
consequently,  six  months  from  that  time,  or  about  the  4th  of  January,  it 
will  rise  in  the  east,  just  when  the  sun  is  setting  in  the  west,  and  will 
come  to  the  meridian  at  midnight ;  being  then  exactly  opposite  to 
the  sun. 

Now  as  the  stars  gain  upon  the  sun  at  the  rate  of  two  hours  every 
month,  it  follows  that  the  center  of  this  constellation  will,  on  the  1 7th  of 
February,  come  to  the  meridian  three  hours  earlier,  or  at  9  o'clock  in  the 
evening. 

It  would  be  a  pleasant  exercise  for  students  to  propose  questions  to 
each  other,  somewhat  like  the  following: — 'What  zodiacal  constellation 
will  rise  and  set  with  the  sun  to-day  ]  What  one  will  rise  at  sun-setting  1 
What  constellation  is  three  hours  high  at  sun-set,  and  where  will  it  be  at 
9  o'clock  ?  What  constellation  rises  two  hours  before  the  sun  1  How 
many  days  or  months  hence,  and  what  hour  of  the  evening  or  morning, 
and  in  what  part  of  the  sky  shall  we  see  the  constellation  whose  center  is 
now  where  the  sun  isl  &c.,  &c. 

In  solving  these  and  similar  questions,  it  may  be  remembered  that  the 
sun  is  in  the  vernal  equinox  about  the  21st  of  March,  from  whence  it 
advances  through  one  sign  or  constellation  every  succeeding  month  there- 
after ;  and  that  each  constellation  is  one  month  in  advance  of  the  sign 
of  that  name  :  wherefore,  reckon  Pisces  in  March,  Aries  in  April,  Taurus 
in  May,  and  Gemini  in  June,  &c.  ;  beginning  with  each  constellation  at 
the  21st,  or  22d  of  the  month. 

Gemini  contains  eighty-five  stars,  including  two 
of  the  2d,  four  of  the  3d,  and  six  of  the  4th  magni- 
tudes. It  is  readily  recognised  by  means  of  the  twro 
principal  stars,  Castor  and  Pollux,  a  and  ]3,  of  the  2d 
magnitude,  in  the  head  of  the  Twins,  about  4j° 
apart. 

There  being  only  11  minutes  difference  in  the 
transit  of  these  two  stars  over  the  meridian,  they 
may  both  be  considered  as  culminating  at  9  o'clock 
about  the  24th  of  February.  Castor,  in  the  head 
of  Castor,  is  a  star  of  the  2d  magnitude,  4^°  N.  W. 


CONSTELLATION  OF  GEMINI.  87 

of  Pollux,  and  is  the  northernmost  and  the  brightest 
of  the  two.  Pollux  is  a  star  of  the  2d  magnitude, 
in  the  head  of  Pollux,  and  is  4j°  S.  E.  of  Castor. 
This  is  one  of  the  stars  from  which  the  moon's 
distance  is  calculated  in  the  Nautical  Almanac. 

"  Of  the  famed  Ledean  pair, 

One  most  illustrious  star  adorns  their  sign, 
And  of  the  second  order  shine  twin  lights." 

The  relative  magnitude  or  brightness  of  these 
stars  has  undergone  considerable  changes  at  differ- 
ent periods  ;  whence  it  has  been  conjectured  by 
various  astronomers  that  Pollux  must  vary  from 
the  1st  to  the  3d  magnitude.  But  Herschel,  who 
observed  these  stars  for  a  period  of  twenty-five 
years,  ascribes  the  variation  to  Castor,  which  he 
found  to  consist  of  two  stars,  very  close  together, 
the  less  revolving  about  the  larger  once  in  342 
years  and  two  months. 

Bradly  and  Maskelyne  found  that  the  line  joining  the  two  stars  which 
form  Castor  was,  at  all  times  of  the  year,  parallel  to  the  line  joining  Castor 
and  Pollux  ;  and  that  both  of  the  former  move  around  a  common  center 
between  them,  in  orbits  nearly  circular,  as  two  balls  attached  to  a  rod 
would  do,  if  suspended  by  a  string  affixed  to  the  center  of  gravity  between 
them. 

"  These  men,"  says  Dr.  Bowditch,  "  were  endowed  with  a  sharpness 
of  vision,  and  a  power  of  penetrating  into  space,  almost  unexampled  in 
the  history  of  astronomy." 

About  20°  S.  W.  of  Castor  and  Pollux,  and  in  a  line  nearly  parallel 
with  them,  is  a  row  of  stars  3°  or  4°  apart,  chiefly  of  the  3d  and  4th 
magnitudes,  which  distinguish  the  feet  of  the  twins.  The  brightest  of 
these  is  Alhena,  y,  in  Pollux's  upper  foot ;  the  next  small  star  S.  of  it,  is 
in  his  other  foot :  the  two  upper  stars  in  the  line  next  above  y,  mark 
Castor's  feet 

This  row  of  feet  is  nearly  two-thirds  of  the  distance  from  Pollux  to 
Betelguese  in  Orion,  and  a  line  connecting  them  will  pass  through 
Alhena,  the  principal  star  in  the  feet.  About  two-thirds  of  the  distance 
from  the  two  in  the  head  to  those  in  the  feet,  and  nearly  parallel  with 
them,  there  is  another  row  of  three  stars  about  6°  apart,  which  mark  the 
knees. 

There  are,  in  this  constellation,  two  other  remarkable  parallel  rows, 
lying  at  right  angles  with  the  former ;  one,  leading  from  the  head  to  the 
foot  of  Castor,  the  brightest  star  being  in  the  middle,  and  in  the  knee ;  the 


88         GEOGRAPHY  OF  THE  HEAVENS. 

other,  leading  from  the  head  to  the  foot  of  Pollux,  the  brightest  star,  called 
Wasat,  <f,  being  in  the  body,  and  £  next  below  it,  in  the  knee. 

Wasat  is  in  the  ecliptic,  and  very  near  the  center  of  the  constellation. 
The  two  stars,  /u  and  Tejat,  »,  in  the  northern  foot,  are  also  very  rieur 
the  ecliptic:  Tejat  is  a  small  star  of  between  the  4th  and  5th  magnitudes, 
2°  W.  of  fj. ,  and  deserves  to  be  noticed  because  it  marks  the  spot  of  the 
summer  solstice,  in  the  tropic  of  Cancer,  just  where  the  sun  is,  on  the 
longest  day  of  the  year,  and  is  moreover,  the  dividing  limit  between  the 
torrid  and  the  N.  temperate  zone. 

Propus,  also  in  the  ecliptic,  2^°  W.  of  x,  is  a  star  of  only  the  5th 
magnitude,  but  rendered  memorable  as  being  the  star  which  served  fcr 
many  years  to  determine  the  position  of  the  planet  Herschel,  after  its  first 
discovery. 

Thus  as  we  pursue  the  study  of  the  stars,  we  shall  find  continually  new 
and  more  wonderful  developments  to  engage  our  feelings  and  reward  our 
labor.  We  shall  have  the  peculiar  satisfaction  of  reading  the  same  volume 
that  was  spread  out  to  the  patriarchs  and  poets  of  other  ages,  of  admiring 
what  they  admired,  and  of  being  led  as  they  were  led,  to  look  upon  these 
lofty  mansions  of  being  as  having,  above  them  all,  a  common  Father  with 
ourselves,  "  who  ruleth  in  the  armies  of  heaven,  and  bringeth  forth  their 
hosts  by  number." 

TELESCOPIC     OBJECTS. 

A  RICH  CLUSTKR. — A.  R.  =  5  h.  59  m.  01  s.  Dec.  =  24°  21'  3". 
Near  Castor's  right  foot.  A  very  fine  object,  consisting  of  a  crowd  of 
stars  from  the  9th  to  the  1 6th  magnitudes. 

Discovered  by  Messier,  1764. 

A  CLUSTER.— A.  R.  =  6  h  45  m.  56  s.  Dec.  =  -f  18°  10'  5". 
On  the  calf  of  the  right  leg  of  Pollux  ;  consists  of  minute  stars  of  the 
1 2th  and  1 6th  magnitudes,  arranged  somewhat  in  the  shape  of  a  fan,  as 
described  by  former  observers. 

Discovered  by  Sir  Wi  Herschel,  1783. 

7.  GEMIXORUM.— A.  R.  =  7  h.  08  m.  54  s.  Dec.  =  -f-  16°  49' 5". 
A  fine  double  star  on  the  left  thigh  of  Pollux.  A  4$,  white ;  B  12, 
yellowish. 

Discovered  by  Struve,  and  thus  measured. 

Pos.  30°  55'         Dist.  9".56         Epoch  1829.86 

f  GEMIXORUM.—  A.  R.  =  7  h.  10  m.  34  s.  Dec.  =  -f-  22°  16'  3  . 
A  double  star  on  the  right  hip  of  Pollux.  A  3^,  "  pale  white  ; "  B  9, 
«  purple." 

Discovered  by  Herschel,  1781. 

Pos.   I960  54'         Dist.  7".  1 5        Epoch  1829.72     Struve. 

*  GEMI*ORUM.—  A.  R.  =  7  h.  34  m.  47  s.     Dec.  =  -\-  24°  46'  5 
A  double  star  on  the  left  shoulder  of  Pollux.  ';,•<& '4,  orange ;  B  10,  pale 
blue.     The  minute  companion  of  this  star  was  pointed  out  as  one  of  a 


CONSTELLATION  OF  GEMINI.  89 

few  which  Sir  John  Herschel  thought  deserved  particular  attention,  to 
determine  whether  it  might  not  be  a  satellite  shining  by  reflected  light. 

Discovered  by  Herschel,  with  his  twenty  feet  reflector. 

Pos.  23109'         Dist.  6".0         Epoch  1838.98     Smyth. 

61  GEMINOKUM.— A.  R.  =  7  h.  17  m.  31  s.  Dec.  =  -{-20° 34'  3". 
A  coarse  double  and  close  double  star,  making  a  quadruple  set  in  the 
loins  of  Pollux.  A  7£,  deep  yellow ;  B  9,  yellowish ;  C  8,  blue ;  D  9, 
bluish. 

D  C  Pos.  =  42°  24'         Dist.  =  6".5        Epoch  1835.85     Smyth. 

A  GEMINORUM.— A.  R.  =  7  h.  24  m.  23  s.  Dec.  =  -f-  32O  14'. 
A  beautiful  double  star  in  the  head  of  Castor,  and  named  Castor.  A  3, 
B  3^,  magnitude.  This  is  one  of  the  interesting  binary  stars.  The 
earliest  position  on  record  is  by  Bradly  and  Pound. 

Pos.  355°  53'         Epoch  1719.84 

This  is  deduced  from  the  recorded  position  of  the  line  joining  the  center 
of  the  components  of  Castor,  with  reference  to  a  third  star  of  the  1 1th 
magnitude;  distant  about  72".  In  1800,  Sir  W.  Herschel  made  the 
pos.  =  293°  03',  since  then  we  find,  among  others,  these  measures. 

Pos.  261°  01"        Dist  4". 358         Epoch   1828.89     Struve.  • 

256    07  5  .280  18:16.88     Encke,  Galle. 

252    49  4  .886  1841.11     Mudler. 

Miidler  has  computed  the  elements  of  the  orbit  of  this  star,  and  found 
for  a  probable  period  232  years.  There  are,  however,  yet  many  difficulties 
in  the  way  of  reliable  results,  and  computers  differ.  More  observations 
are  necessary  to  complete  the  examinations  of  this  interesting  binary 
system. 

38  GEMINORUM.— A.  R.  =  6  h.  45  m.  37  s.     Dec.  =-f-  1 30  22'  6". 
A  double  star  on  the  left  instep  of  Pollux.     A  5£,  B  8,  magnitude.     The 
large  star  yellow,  the  small  one  purple. 
Discovered  by  Herschel  in  1781. 

Pos.   1790  54'         Dist.  7". 95         Epoch  1781.99     Herschel. 
174    53  5  .73  1829.24     Striive. 

172    02  6  .42  1841.27     Mudler. 

Mudler  thinks  this  system  may  be  binary,  in  which  case  its  periodic 
time  cannot  fall  much  below  3000  years. 

A  CLUSTKH.— A.  R.  =  7  h.  28  m.  57  s.  Dec.  =  -f-  21O  55'  7" 
On  the  left  shoulder  of  Pollux. 

Discovered  by  Herschel  in  1783,  and  described  as  "  a  beautiful  clustei 
of  many  large  and  compressed  small  stars,  about  12'  in  diameter." 

H2 


GEOGRAPHY   OF   THE  HEAVENS. 


CANCER. 

THE  CRAB  is  now  the  fifth  constellation  and  fourth 
sign  of  the  Zodiac.  It  is  situated  in  the  ecliptic, 
between  Leo  on  the  E.  and  Gemini  on  the  W.  It 
contains  eighty-three  stars,  of  which  two  are  of  the 
4th  magnitude. 

Beta  is  a  star  of  the  4th  magnitude' in  the  south- 
western claw,  10°N.  E.  of  Procyon,a  Canis  Minoris, 
and  may  be  known  from  the  fact  that  it  stands  alone, 
or  at  least  has  no  star  of  th^.  same  magnitude  near 
it.  It  is  midway  between  Procyon  and  Acubens. 

Acubens,  a,  is  a  star  of  the  5th  magnitude,  in  the 
southeastern  claw,  10°  N.  E.  of  Beta,  and  nearly  in 
a  straight  line  with  it  and  Procyon.  It  may  be 
otherwise  distinguished  by  its  standing  between 
two  very  small  stars  close  by  it  in  the  same  claw. 

Tegmine,  £,  the  last  in  the  back,  appears  to  be  a 
small  star,  of  between  the  5th  and  6th  magnitudes, 
8J°  in  a  northerly  direction  from  Beta.  It  is  a 
treble  star,  and  to  be  distinctly  seen,  requires  very 
favorable  circumstances!  Two  of  them  are  so  near 
together  that  it  requires  a  telescopic  power  of  300 
to  separate  them. 

About  7°  northeasterly  from  Tegmine,  is  a  nebu- 
lous cluster  of  very  minute  stars,  in  the  crest  of 
Cancer,  sufficiently  luminous  to  be  seen  by  the 
naked  eye.  It  is  situated  in  a  triangular  position 
with  regard  to  the  head  of  the  Twins  and  the  Little 
Dog  It  is  about  20°  W.  of  each.  It  may  other- 
wise be  discovered  by  means  of  two  conspicuous 
stars  of  the  4th  magnitude  lying  one  on  either  side 
of  it,  at  the  distance  of  about  2°,  called  the  northern 
and  southern  Aselli.  By  some  of  the  Orientalists, 
this  cluster  was  denominated  Prassepe,  the  Manger, 
a  contrivance  which  their  fancy  fitted  up  for  the 


CONSTELLATION  OF  CANCER.  91 

accommodation  of  the  Aselli  or  Asses ;  and  it  is  so 
called  by  modern  astronomers.  The  appearance 
of  this  nebula  to  the  unassisted  eye,  is  not  unlike 
the  nucleus  of  a  comet,  and  it  was  repeatedly 
mistaken  for  the  comet  of  1832,  which,  in  the 
month  of  November,  passed  in  its  neighborhood. 

The  southern  Asellus,  marked  6,  is  situated  in  the 
line  of  the  ecliptic,  and  in  connection  with  6  and 
Gemini,  n,  marks  the  course  of  the  earth's  orbit  for 
a  space  of  36°  from  the  solstitial  colure. 

There  are  several  other  double  and  nebulous 
stars  in  this  constellation,  most  of  which  are  too 
small  to  be  seen;  and  indeed,  the  whole  constella- 
tion is  less  remarkable  for  the  brilliancy  of  its  stars 
than  any  other  in  the  Zodiac. 

The  sun  arrives  at  the  sign  Cancer  about  the  21st 
of  June,  but  does  not  reach  the  constellation  until  the 
23d  of  July. 

The  mean  right  ascension  of  Cancer  is  128°.  It 
is  consequently  on  the  meridian  the  3d  of  March. 

A  few  degrees  S.  of  Cancer,  and  about  17°  E.  of  Procyon,  are  four 
stars  of  the  4th  magnitude,  3°  or  4°  apart,  which  mark  the  head  of 
Hydra. 

The  beginning  of  the  sign  Cancer  (riot  the  constellation)  is  called  the 
Tropic  of  Cancer,  and  when  the  sun  arrives  at  this  point,  it  has  reached 
its  utmost  limit  of  north  declination,  where  it  seems  to  remain  stationary 
a  few  days,  before  it  begins  to  decline  again  to  the  south.  This  station- 
ary attitude  of  the  sun  is  called  the  summer  aulislice  /  from  two  Latin 
words  signifying  the  suns  standing  .-till.  The  distance  from  the  Ihv.t 
point  of  Cancer  to  the.  equinoctial,  which  at  present,  is  23°  27 -f' ,  is  called 
the  obliquity  of  the  ecliptic.  It  is  a  remarkable  and  well  ascertained 
fact,  that  this  is  continually  growing  less  and  less.  The  tropics  are 
slowly  and  steadily  approaching  the  equinoctial,  at  the  rate  of  about  half 
a  second  every  year ;  so  that  the  sun  does  not  now  come  so  far  north  of 
the  equator  in  summer,  nor  decline  so  far  south  in  winter,  as  it  must  have 
done  at  the  creation,  by  nearly  a  degree. 

TELESCOPIC    OBJECTS. 

••' 

11  CANCRI.— A.  R.  =  7  h.  59  m.  02  s.  Dec.  =  -f-  27°  56'  4". 
A  close  double  star  between  the  head  of  Pollux  and  the  preceding  claw 
of  Cancer.  A  7,  B  12,  magnitude. 


92  GEOGRAPHY   OF  THE  HEAVENS. 

Pos.  218052'         Dist.  3".  18         Epoch  1828.26     Struve. 

£  CANCEL— A.  R.  =  8  h.  03  m.  02  s.     Dec.  =  -f  18°  07'  5".     A 

fine  triple  star  just  below  the  following  claw  of  Cancer.     A  6,  yellow ; 
B  7,  orange  ;  C  7^,  yellowish. 
Discovered  by  the  elder  Herschel. 

A  B  Pos.       3028'      Dist.  =  1".00      Epoch  1781.90  }„       ,, 
AC  181     44  8.05  1781.90  5 HerscheL 

A  B  21     30  1    .13  18:W.27  ?  Qf  .. 

AC  148     18  5.48  1833.27 }       uve< 

AB  1    016"  1   .050  1841.31  },,„„ 

AC-  147    54  5.008  184 1.31  5 M    ller' 

This  is  a  very  remarkable  object.  Captain  Smyth  deduced  a  period  for 
A  and  B  of  sixty  years,  while  C  performs  its  revolution  about  the  other 
two  in  500  or  600  years.  Here  is  a  ternary  system  ;  three  suns  re- 
volving about  their  common  center  of  gravity,  and  doubtless  each  attended 
by  a  retinue  of  planets.  How  wonderful  must  be  the  heavens  to  the  in- 
habitants of  the  planets  attached  to  this  triple  system.  Imagine  a  yellow 
sun  rising,  an  orange  one  on  the  meridian,  while  a  purple  or  blue,  or  red 
one,  may  be  in  the  act  of  sinking  below  the  horizon  !  Again,  the  powerful 
analysis  with  which  man  urges  his  way  through  the  intricacies  of  our 
simple  solar  system,  would  utterly  fail  to  trace  the  career  of  a  planet  sub- 
jected to  the  contending  influences  of  three  grand  orbs  like  the  sun.  May 
we  not  infer,  from  this  fact,  the  existence  of  races  of  a  higher  order  of 
intellect  in  the  planets  of  these  ternary  systems  1 

4>  2  CAXCRI.— A.  R.  =  8  h.  17  m.  6  s.  Dec.  =  -f-  2?o  27'  2". 
A  close  double  star  above  the  northern  legs  of  Cancer.  A  6,  B  6^, 
magnitude.  Its  position  is  probably  fixed. 

Pos.  2120  01'         Dist.  4".  563         Epoch  1829.45     Struve. 

v  I  CANCRI.  —A.  R.  =  8  h.  1 7  m  08  s.  Dec.  =  -}-  25O  03'  3".  A 
double  star  on  the  crab's  northern  middle  leg.  A  7.  B  7^. 

Discovered  by  Herschel,  1782.     Measured  by  him  as  follows: 

Pos.  57°5l'         Epoch  17S3.07     Herschel. 

In  1822,  Sir  James  South  and  Sir  John  Herschel  found  the  position  to 
be  37C  47',  whence  a  rapid  retrograde  motion  was  inferred,  but  all  subse- 
quent measures  disprove  this  inference,  and  indicate  a  direct  motion. 

Pos.   390  04'         Dist.   5".7-23         Epoch  1841.35     Midler. 

<T  CANCHT  —  A.  R.  =  8  h.  35  m.  35  s.  Dec.  =  -f  ISO  44'  4".  A 
difficult  double  star  under  the  crab's  mouth.  A  4^,  B  15,  magnitude. 

/  CAXCRI.— A.  R.  =  8  h.  37  m.  00  s.  Dec.  =  29°  20'  4".  A 
double  star  at  the  end  of  the  crab's  northern  claw.  A  5^,  pale  orange ; 
B  8.  clear  blue.  This  is  the  first  double  star  I  ever  saw.  In  July  1842, 
I  had  the  pleasure  of  examining  it  at  the  observatory  of  Sir  James  £fcuth, 
Kensington.  The  colors  were  distinct  and  beautifully  contrasted. 

Pos.  307°  06'         Dist.  30" .46         Epoch  1828.04    Stmve. 

No  material  change  has  occurred  in  fifty-four  years,  the  time  since  its 
discovery  by  Herschel. 


CONSTELLATION  OF  CANCER.  93 


67  MKSSIER,  CANCRL— A.  R.  =  8  h.  42  m.  26  s.  Dec.  =  4-12° 
2:3'  6".  A  rich  but  scattered  cluster,  at  the  root  of  the  southern  claw  of 
Cancer.  It  is  readily  resolved,  and  with  a  power  of  1 57  Hcrschel  counted 
two  hundred  stars  of  various  magnitudes,  from  the  9th  to  the  smallest 
magnitude.  I  have  frequently  examined  this  splendid  object,  and  from 
its  appearance  suppose  it  to  be  one  of  the  near  "  island  universes. ' 

Discovered  by  Messier,  1 780. 

a-  2  CANCEL— A.  R.  =  8  h.  44  m.  28  s.  Dec.  =  -f  31°  10'  9".  A 
close  double  star  over  the  crab's  northern  claw.  A  5^,  B  7  magnitude. 

Discovered  by  Sir  W.  Herschel.  1782. 

Pos.  3:33-  18'         Dist.  =  1".51         Epoch  '1829.71     Struve. 

There  is  little  evidence  of  any  change  of  position,  though  the  measures 
recorded  are  far  from  coincident. 

a-  4  CANCEL— A.  R.  =  8  h.  51  m.  35  s.  Dec.=  -f-  32°  52'  4".  A 
close  double  star,  following  the  crab's  northern  claw.  A  6,  white ;  B 
9,  blue. 

Discovered  by  South,  1825. 

Pos.  137°  47'         Dist.  4".50         Epoch  1831.16     Struve. 


CAN  IS    MINOR,     -y  ,.] 

THE  LITTLE  DOG. — This  small  constellation  is 
situated  about  5°  N.  of  the  equinoctial,  and  mid- 
way between  Canis  Major  and  the  Twins.  It 
contains  fourteen  stars,  of  which  two  are  very 
brilliant.  The  brightest  star  is  called  Procyon, 
marked  a.  It  is  of  the  1st  magnitude,  and  is  about 
4°  S.  E.  of  the  next  brightest,  Gomeha,  marked  /3, 
which  is  of  the  3d  magnitude. 

These  two  stars  resemble  the  two  in  the  head  of 
the  Twins.  Procyon,  in  the  Little  Dog,  is  23°  S. 
of  Pollux  in  Gemini,  and  Gomelza  is  about  the  same 
distance  S.  of  Castor. 

A  great  number  of  geometrical  figures  may  be 
formed  of  the  principal  stars  in  the  vicinity  of  the 
Littie  Dog.  For  example  ;  Procyon  is  23°  S.  of 
Pofrax,  and  26°  E.  of  Betelguese,  and  forms  with 
them  a  large  right  angled  triangle.  Again,  Procyon 
is  equidistant  from  Betelguese  and  Sirius,  and  forms 
with  them  an  equilateral  triangle  whose  sides  are 


94  GEOGRAPHY   OF  THE  HEAVENS. 

each  about  26°.  If  a  straight  line,  connecting 
Procyon  and  Sirius,  be  produced  23°  farther,  it  will 
point  out  Phaet,  in  the  Dove. 

Procyon  is  often  taken  for  the  name  of  the  Little 
Dog,  or  for  the  whole  constellation,  as  Sirius  is  for 
the  greater  one ;  hence  it  is  common  to  refer  to 
either  of  these  constellations  by  the  name  of  its 
principal  star.  Procyon  comes  to  the  meridian 
fifty- three  minutes  after  Sirius,  on  the  24th  of 
February ;  although  it  rises,  in  this  latitude,  about 
half  an  hour  before  it.  For  this  reason,  it  was  called 
Procyon,  from  two  Greek  wrords  which  signify  (Ante 
Canis]  "  before  the  dog." 

"  Canicula,  fourteen  thy  stars  ;  but  far       _, 
Above  them  all,  illustrious  through  the  skies, 
Beams  Procyon  :  justly  by  Greece  thus  called 
The  bright  forerunner  of  the  greater  -Dog1." 

From  an  irregularity  in  the  annual  proper  motion 
of  Procyon,  Bessel  concluded  that  it  was  disturbed 
by  some  invisible  opaque  body  of  vast  size,  sunk  in 
space,  near  Procyon.  Striive  has  recently  cast  a 
doubt  on  the  reality  of  this  irregularity,  and  thinks 
it  is  due  to  imperfect  observations. 


CONSTELLATION   OF    MONOCRROS.  95 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    VIII. 

MONOCEROS — THE  UNICORN. 
CANIS  MAJOR  —  THE  GREAT  DOG. 
LEPUS — THE   HARE. 
THE  PRINTING  PRESS. 

Favorably  situated  for  examination  in  January,  Febru- 
ary and  March. 

MONOCEROS. 

THE  UNICORN. — This  is  a  modern  constellation, 
which  was  made  out  of  the  unformed  stars  of  the 
ancients  that  lay  scattered  over  a  large  space  of 
the  heavens  between  the  two  Dogs.  It  extends  a 
considerable  distance  on  each  side  of  the  equinoctial, 
and  its  center  is  on  the  same  meridian  with  Procyen. 

It  contains  thirty-one  small  stars,  of  which  the 
seven  principal  ones  are  of  only  the  5th  magnitude. 
Three  of  these  are  situated  in  the  head,  3°  or  4° 
apart,  forming  a  straight  line  N.  E.  and  S.  W.  about 
9°  E.  of  Betelguese,  in  Orion's  shoulder,  and  about 
the  same  distance  S.  of  Alhena,  in  the  foot  of  the 
Twins. 

The  remaining  stars  in  this  constellation  are 
scattered  over  a  large  space,  and  being  very  small, 
are  unworthy  of  particular  notice.  ^b<* 

TELESCOPIC     OBJECTS. 

104  P.  VI,  MOXOCEROTIS.— A.  R.  =  6  h.  18  m.  30  s.  Dec.  =  -f- 
0°  32'  6".  A  coarse  triple,  or  close  double  star.  A  7^,  B  and  C,  each 
83  magnitude.  As  A  and  B  are  66"  apart,  we  shall  only  have  to  do 
with  B  and  C.  This  is  one  of  Struve's  "  vincinissernae  "  stars.  He 
reports  these  measures. 

Pos.    168048'         Disk  0" .78         Epoch  1825.12 

1 1  MONOCKROTIS.— A.  R.  =  6  h.  21  m.  04  s.     Dec.  =  —  6°  56'  1". 


96         GEOGRAPHY  OF  THK  HEAVENS. 

A  fine  triple  star  in  the  right  fore  leg  of  Monoceros.  A  6^,  B  7,  C  8, 
magnitude. 

Discovered  by  Sir  W.  Herschel,  and  by  him  said  to  be  one  of  the  most 
beautiful  sights  in  the  heavens. 

A  B  Pos.   101°  44'        Dist.  2".4K3         Epoch  1831.23     Strive. 

A  B  103    41  2  .557  1842.21     Miidler. 

AC  310    00  7  .253  1831/23     Striive. 

AC  311     23  7.205  1842.21     Mildler. 

BC  304    40  9  .452  1842.21     Midler. 

Midler  thinks  this  may  prove  to  be  a  triple  system,  in  which  case  the 
observations  would  indicate  for  A  and  B  a  period  of  nearly  17,000  years, 
and  for  B  and  C  a  period  of  more  than  1,000  years. 

14  MOXOCEROTIS. — A.  R.  =  6  h.  26  m.  06  s.     Dec.  =  -f-  7°  41' 
5".     A  difficult  double  star  in  the  eye  of  the  Unicorn.     A   6,  B   16, 
magnitude.     Smyth's  estimates  are  follows  : 

Pos.  210°  0'         Dist.    10".0         Epoch  1833.87 

15  MONOCEHOTIS.— A.  R.  =  6  h.  32  m.  10s.     Dec.  =  -j-  IQO  02' 
2".     A  triple  star  between  the  ears  of  Monoceros.     A  6,  "  greenish  ;  " 
B  9,  "  pale  grey ; "  C  15,  «  blue." 

Discovered  by  Strive. 

Pos.  A  B  208°  66'        Dist.     2".76         Epoch    1 83 1 .37  ?  Q,  .. 
A  C     12    90  16  ..';8  1831.373 

50  MKSSIKR,  MOXOCEIIOTIS. — A.  R.  =  6  h.  55  m.  1 1  s.  Dec.  =  — 
go  06'  7".  A  large  cluster  in  the  Milky  Way,  on  the  Unicorn's  right 
shoulder,  composed  of  stars  varying  from  the  8th  to  the  16th  magnitude 

Discovered  by  Messier,  1771. 


CANIS    MAJOR. 

THE  GREAT  DOG. — This  interesting  constellation 
is  situated  southward  and  eastward  of  Orion,  and 
is  universally  known  by  the  brilliancy  of  its  prin- 
cipal star,  Sirius,  marked  a,  which  is  apparently  the 
largest  and  brightest  in  the  heavens.  It  glows  in 
the  winter  hemisphere  with  a  luster  which  is  un- 
equaled  by  any  other  star  in  the  firmament. 

Its  distance  from  the  earth,  though  computed  at 
twenty  millions  of  millions  of  miles,  has  been  con- 
sidered less  than  that  of  any  other  star  :  a  distance, 
however,  so  great  that  a  cannon  ball,  which  flies  at 
the  rate  of  nineteen  miles  a  minute,  would  be  two 
millions  of  years  in  passing  over  the  mighty  inter- 


CONSTELLATION  OF  CANIS   MAJOR.       *          97 

val ;  while  sound,  moving  at  the  rate  of  thirteen 
miles  a  minute,  would  reach  Sirius  in  little  less 
than  three  millions  of  years. 

It  may  be  shown  in  the  same  manner,  that  a  ray  of  light,  which  occu- 
pies only  eight  minutes  and  thirteen  seconds  in  coming  to  us  from  the 
sun,  which  is  at  the  rate  of  nearly  two  hundred  thousand  miles  a  second, 
would  be  three  years  and  eighty-two  days  in  passing  through  the  vast 
space  that  lies  between  Sirius  and  the  earth.  Consequently,  were  it 
blotted  from  the  heavens,  its  light  would  continue  visible  to  us  for  a  period 
of  three  years  and  eighty-two  days  after  it  had  ceased  to  be. 

If  the  nearest  stars  give  such  astonishing  results,  what  shall  we  say  of 
those  which  are  situated  a  thousand  times  as  far  beyond  these,  as  these 
are  from  us  1 

In  the  remote  ages  of  the  world,  when  every  man 
was  his  own  astronomer,  the  rising  and  setting  of 
Sirius,  or  the  Dog-star,  as  it  is  called,  was  watched 
with  deep  and  various  solicitude.  The  ancient 
Thebans,  who  first  cultivated  astronomy  in  Egypt, 
determined  the  length  of  the  year  by  the  number 
of  its  risings.  The  Egyptians  watched  its  rising 
with  mingled  apprehensions  of  hope  and  fear ;  as 
it  was  ominous  to  them  of  agricultural  prosperity 
or  blighting  drought.  It  foretold  to  them  the  rising 
of  the  Nile,  which  they  called  Siris,  and  admonish- 
ed them  when  to  sow.  The  Romans  were  accus- 
tomed yearly,  to  sacrifice  a  dog  to  Sirius  to  render 
him  propitious  in  his  influence  upon  their  herds 
and  fields.  The  eastern  nations  generally  believed 
the  rising  of  Sirius  would  be  productive  of  great 
heat  on  the  earth. 

Thus  Virgil : 

"  Turn  steriles  exurere  Sirius  agros : 

Ardebant  herbs,  et  victum  seges  segra  negabat." 

"  Parched  was  the  grass,  and  blighted  was  the  corn  . 

Nor  'scape  the  beasts ;  for  Sirius,  from  on  high, 
With  pestilential  heat  infects  the  sky." 

Accordingly,  to  that  season  of  the  year  when 
Sirius  rose  with  the  sun  and  seemed  to  blend  its 
own  influence  with  the  heat  of  that  luminary,  the 


98         GEOGRAPHY  OF  THE  HEAVENS. 

ancients  gave  the  name  of  Dog-days,  (Dies  Canicii- 
lares).  At  that  remote  period  the  Dog-days  com- 
menced on  the  4th  of  August,  or  four  days  afler  the 
summer  solstice,  and  lasted  forty  days,  or  until  the 
14th  of  September.  At  present  the  Dog-days  begin 
on  the  3d  of  July,  and  continue  to  the  llth  of  August, 
being  one  day  less  than  the  ancients  reckoned. 

Hence,  it  is  plain  that  the  Dog-days  of  the  mod- 
erns have  no  reference  whatever  to  the  rising  of 
Sirius,  or  any  other  star,  because  the  time  of  their 
rising  is  perpetually  accelerated  by  the  precession 
of  the  equinoxes  :  they  have  reference  then  only 
to  the  summer  solstice,  which  never  changes  its 
position  in  respect  to  the  seasons. 

The  time  of  Sirius'  rising  varies  with  the  latitude  of  the  place,  and  in 
the  same  latitude,  is  sensibly  changed  after  a  course  of  years,  on  account 
of  the  precession  at  the  equinoxes.  This  enables  us  to  determine  with 
approximate  accuracy,  the  dates  of  many  events  of  antiquity,  which  can- 
not be  well  determined  by  other  records.  We  do  not  know,  for  instance, 
in  what  precise  period  .of  the  world  Hesiod  flourished.  Yet  he  tells 
us,  in  his  Opera  el  Dies,  lib.  ii.  v.  185,  that  Arcturus  in  his  time  rose 
heliacally,  sixty  days  after  the  winter  solstice,  which  then  was  in  the  9th 
degree  of  Aquarius,  or  39°  beyond  its  present  position.  Now  39°  :  54£" 
=  2794  years  since  the  time  of  Hesiod,  which  corresponds  very  nearly 
with  history. 

When  a  star  rose  at  sun-setting,  or  set  at  sun-rising,  it  was  called  the 
Achronical  rising  or  setting.  When  a  planet  or  star  appeared  above  the 
horizon  just  before  the  sun,  in  the  morning,  it  was  called  the  Htliacal 
rising  of  the  star ;  and  when  it  sunk  below  the  horizon  immediately  alter 
the  sun,  in  the  evening,  it  was  called  the  Heliacal  setting.  According 
to  Ptolemy,  stars  of  thejirst  magnitude  are  seen  rising  and  setting  when 
the  sun  is  12°  below  the  horizon ;  stars  of  the  2d  magnitude  require  the 
sun's  depression  to  be  13°  ;  stars  of  the  3d  magnitude,  14°,  and  so  on, 
allowing  one  degree  for  each  magnitude.  The  rising  and  setting  of  the 
stars  described  hi  this  way,  since  this  mode  of  description  often  occurs  in 
Hesiod,  Virgil,  Columella,  Ovid,  Pliny,  &c.,  are  called  poetical  rising  and 
setting.  They  served  to  mark  the  times  of  religious  ceremonies,  the 
seasons  allotted  to  the  several  departments  of  husbandry,  and  the  over- 
flowing of  the  Nile. 

The  student  may  be  perplexed  to  understand  how 
the  Dog-star,  which  he  seldom  sees  till  mid- winter, 
should  be  associated  with  the  most  fervid  heat  of 
summer.  This  is  explained  by  considering  that 


CONSTELLATION  OF  CANIS  MAJOR.  99 

this  star,  in  summer,  is  over  our  heads  in  the  day- 
timg,  and  in  the  lower  hemisphere  at  night.  As 
"  thick  the  floor  of  heaven  is  inlaid  with  patines  of 
bright  gold,"  by  day,  as  by  night ;  but  on  account 
of  the  superior  splendor  of  the  sun,  we  cannot  see 
them. 

Sirius  is  easily  recognised,  being  the  brightest  star 
in  the  heavens,  and  is  pointed  out  by  the  direction 
of  the  Three  Stars  in  the  belt  of  Orion .  Its  distance 
from  them  is  about  23°.  It  comes  to  the  meridian 
at  9  o'clock  on  the  llth  of  February. 

Mirzam,  marked  0,  in  the  foot  of  the  Dog,  is  a  star 
of  the  2d  magnitude,  5£°  W.  of  Sirius.  A  little 
above,  and  4°  or  5°  to  the  left,  there  are  three  stars 
of  the  3d  and  4th  magnitudes,  forming  a  triangular 
figure  somewhat  resembling  a  dog's  head.  The 
brightest  of  them,  on  the  left,  is  called  Muliphen, 
marked  y.  It  entirely  disappeared  in  1670,  and 
was  not  seen  again  for  more  than  twenty  years. 
Since  that  time  it  has  maintained  a  steady  luster. 

Wcsen,  marked  5,  is  a  star  of  the  3d  magnitude, 
in  the  back,  11°  S.  S.  E.  of  Sirius,  with  which,  and 
Mirzam  in  the  paw,  it  makes  an  elongated  triangle. 
The  two  hinder  feet  are  marked  by  Naos  and 
Lambda,  stars  of  the  3d  and  4th  magnitudes,  situ- 
ated about  3°  apart,  and  12°  directly  S.  of  the  fore 
foot.  This  constellation  contains  thirty-one  visible 
stars,  including  one  of  the  1st  magnitude,  four  of 
the  2d,  and  two  of  the  3d  ;  all  of  which  are  easily 
traced  out  by  the  aid  of  the  map. 

TELESCOPIC    OBJECTS. 

y  1  CAITIS  MAJORIS.— A.  R.  =  6  h.  29  m.  23  s.  Dec.  =  —  18° 
32'  0".  A  double  star  in  the  Greater  Dog's  left  knee,  about  3°  south- 
west of  Sirius.  A  6^,  B  8,  magnitude. 

Pos.  261°  36'        Dist.  17". 34        Epoch  1842.82     Main. 

at  CAMS  MAJOR  is,  SIRIUS. — A.  R.  =  6  h  38  m.  06  s  1'ec.  =  — 
16'  30'  1".  A  star  of  the  first  magnitude  in  the  mouth  of  the  Greater 


100  GEOGRAPHY  OF  THE  HEAVENS. 

Dog,  the  most  brilliant  of  all  the  fixed  stars.  The  telescopic  appearance 
of  this  object  must  be  seen  to  be  appreciated.  Long  before  it  enters  the  field 
of  the  telescope,  its  coming  is  indicated  by  a  gradually  brightening  dawn, 
which  slowly  increases  in  splendor,  until  the  star  enters  with  its  full  blaze, 
too  powerful  to  be  borne  by  the  sight. 

Its  entrance  and  disappearance  resemble  the  rising  and  setting  of 
the  sun. 

Sirius  was  long  regarded  as  the  nearest  of  all  the  fixed  stars,  from  its 
exceeding  brilliancy.  Long  and  delicate  measures  have  been  made  to 
determine  its  parallax,  but  without  satisfactory  results.  Yet  its  proper 
motion  is  great,  and  readily  deduced  from  a  few  years  of  observations. 
On  a  comparison  of  the  place  of  Sirius,  as  laid  down  by  the  earliest  Greek 
astronomers,  with  its  present  position,  and  computing  the  changes  due  to 
the  present  rate  of  proper  motion.  Bessel  deduces  the  curious  fact  that 
the  annual  proper  motion  is  not  uniform  !  This  is  true  of  a  few  other 
fixed  stars.  To  account  for  this  phenomenon,  Bessel  conceives  that 
Sirius  is  subjected  to  the  influence  of  some  vast  body,  which,  from  the 
fact  of  its  being  non-luminous,  has  never  been  discovered.  How  wonder- 
ful would  it  be,  if  by  a  rigid  scrutiny  of  the  deviations  of  the  proper  motions 
of  Sirius  from  uniformity,  we  should  be  led  to  a  knowledge  of  the  position 
in  space  of  this  dark  disturbing  body,  of  whose  place  and  existence, 
indeed,  the  sight  can  reveal  to  us  nothing. 

The  latest  and  best  measures  for  parallax  are  by  Henderson  and 
McLear,  who  found  for  the  angle  subtended  by  the  radius  of  the  earth's 
orbit,  at  a  distance  equal  to  Sirius  0".23.  or  about  one  quarter  of  one 
second  of  space.  In  case  we  adopt  this  as  the  true  parallax,  the  distance 
of  Sirius  must  be  nearly  eighty  millions  of  millions  of  miles,  and  from  its 
splendor  we  are  able  to  infer,  with  certainty,  that  its  magnitude  is  very 
much  greater  than  that  of  our  sun.  Indeed,  Dr.  Walliston,  assuming 
the  distance  to  be  but  half  the  above,  concludes  from  his  photometrical 
measures,  that  Sirius,  if  seen  as  near  as  the  sun,  would  present  a  diameter 
four  times  greater  than  that  of  the  sun. 

^  CANTS  MAJORIS.— A.  R.  =  6  h.  48  m.  46  s.     Dec.  ==  —  13°  50' 
5".     A  double  star  on  the  Dog's  right  ear.     A  ft£,  yellow ;  B  9£,  grey. 
Discovered  by  Struve,  who  gives  these  measures. 
Pos.  343031'         Dist,  3".22         Epoch  1831.30 

14  HEHSCHEL,  VII  CANIS  MAJORTS.— A.  R.  =  6  h,  52  m.  10  e. 
Dec.  =  —  13°  29'  2".  A  cluster  of  stars  back  of  the  Dog's  head,  about 
20'  in  diameter.  The  stars  range  from  the  8th  to  the  1 1th  magnitude. 

Discovered  by  Herschel. 

12  HERSCHEL,  VII  CAXIS  MAJORIS.— A.  R.  =  7  h.  10  m.  35  s. 
Dec.  =  —  15°  21'  4".  A  cluster  of  stars  between  the  Dog  and  Unicorn ; 
and  consists  principally  of  stars  of  the  10th  magnitude. 

Discovered  by  Miss  Herschel. 


CONSTELLATION   OF   LEPUS.  101 


L  E  P  U  S  . 

THE  HARE. — This  constellation  is  situated  direct- 
ly south  of  Orion,  and  comes  to  the  meridian  at  the 
same  time  ;  namely,  on  the  24th  of  January.  It  has 
a  mean  declination  18°  S.  and  contains  nineteen 
small  stars,  of  which,  one  is  of  the  2d,  one  of  the  3d, 
and  six  of  the  4th  magnitudes.  It  may  be  readily 
distinguished  by  means  of  four  stars  of  the  3d  mag- 
nitude, in  the  form  of  an  irregular  square,  or 
trapezium. 

Zcta,  of  the  4th  magnitude,  is  the  first  star,  and 
is  situated  in  the  back,  5°  S.  of  Saiph,  in  Orion. 
About  the  same  distance  below  £  are  the  four  prin- 
cipal stars,  in  the  legs  and  feet.  These  form  the 
square.  They  are  marked  a,  js,  */,6.  a  and  ,3,  other- 
wise called  Arneb,  form  the  N.  W.  end  of  the  tra- 
pezium, and  are  about  3°  apart,  y  and  6  form  the 
S.  E.  end,  and  are  about  2j°  apart.  The  upper 
right  hand  one,  which  is  Arneb,  is  the  brightest  of 
the  four,  and  is  near  the  center  of  the  constellation. 
Four  or  five  degrees  S.  of  Rigel  are  four  very  minute 
stars,  in  the  ears  of  the  Hare. 

TELESCOPIC     OBJECTS. 

t  LEPORFS.— A.  R.  =  5  h.  04  m.  50  s.     Dec.  =  —  12°  03'  9".     A 
double  star  in  the  left  ear  of  the  Hare.     A  4-i,  B  12,  magnitude. 
Pos.  *.'9°  31'         Dist.  12". 34         Epoch  1782.69     Herschel. 
3:r/    39  12  .81  1832.25    .Strive. 

H  LEPOUTS. — A.  R.  =  5  h.  5  m.  51  s.     Dec.  =  —  13°  08'  0".     A 
double  star  at  the  root  of  the  ear.     A  5,  B  9,  magnitude. 

Pos.  358°  68'         Dist.  3".()53         Epoch  1832.23     Struve. 

12 


102  GEOGRAPHY  OF  THE  HEAVENS. 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    IX.     ' 

LEO  MAJOR — THE  GREAT  LION. 
SEXTANS — THE  SEXTANT. 

Favorably  situated  for  examination  in  March,  April, 
and  May. 

LEO. 

THE  LION. — This  is  one  of  the  most  brilliant  con- 
stellations in  the  winter  hemisphere,  and  contains 
an  unusual  number  of  very  bright  stars.  Tt  is  situ- 
ated next  E.  of  Cancer,  and  directly  S.  of  Leo 
Minor  and  the  Great  Bear. 

The  Hindoo  Astronomer,  Varaha  says,  "  Certainly  the  southern  sol- 
stice was  once  in  the  middle  of  Asleha  (Leo);  the  northern  in  the  first 
degree  of  Dhanishta  "  (Aquarius).  Since  that  time,  the  solstitial,  as 
well  as  the  equinoctial  points,  have  gone  backwards  on  the  ecliptic  75°. 
This  divided  by  50|",  gives  5373  years ;  which  carry  us  back  to  the 
year  of  the  world  464.  Sir  W.  Jones,  says  that  Varaha  lived  when  the 
solstices  were  in  the  first  degrees  of  Cancer  and  Capricorn ;  or  about  400 
years  before  the  Christian  era. 

Leo  is  the  fifth  sign,  and  the  sixth  constellation, 
of  the  Zodiac.  The  mean  right  ascension  of  this 
extensive  group  is  150°,  or  10  hours.  Its  center  is 
therefore  on  the  meridian  the  6th  of  April.  Its 
western  outline,  however,  comes  to  the  meridian 
on  the  18th  of  March,  while  its  eastern  limit  does 
not  reach  it  before  the  3d  of  May. 

This  constellation  contains  ninety-five  visible 
stars,  of  which  one  is  of  the  1st  magnitude,  one  of 
the  2d,  six  of  the  3d,  and  fifteen  of  the  4th. 

The  principal  star  in  this  constellation  is  of  the 
1st  magnitude,  situated  in  the  breast  of  the  animal, 
marked  a,  and  named  Regulus,  from  the  illustrious 
Roman  consul  of  that  name. 


CONSTELLATION   OF   LEO.  103 

It  is  situated  almost  exactly  in  the  ecliptic,  and 
may  be  readily  distinguished  on  account  of  its 
superior  brilliancy.  It  is  the  largest  and  lowest  of 
a  group  of  five  or  six  bright  stars  which  form  a 
figure  somewhat  resembling  a  sickle,  in  the  neck 
and  shoulder  of  the  Lion.  There  is  a  little  star  of 
the  5th  magnitude  about  2°  S.  of  it,  and  one  of  the 
3d  magnitude  5°  N.  of  it,  which  will  serve  to  point 
it  out. 

Regulus  is  the  brightest  star  in  the  constellation. 
Great  use  is  made  of  Regulus  by  nautical  men,  for 
determining  their  longitude  at  sea.  Its  latitude,  or 
distance  from  the  ecliptic,  is  less  than  J° ;  but  its 
declination,  or  distance  from  the  equinoctial  is  nearly 
13°  N. ;  so  that  its  meridian  altitude  will  be  just 
equal  to  that  of  the  sun  on  the  19th  of  August.  Its 
right  ascension  is  very  nearly  150°.  It  therefore 
culminates  about  9  o'clock  on  the  6th  of  April. 

When  Regulus  is  on  the  meridian,  Castor  and  Pollux  are  seen  about 
40°  N.  W.  of  it,  and  the  two  stars  in  the  Little  Dog,  are  about  the  same 
distance  in  a  S.  W .  direction ;  with  which,  and  the  two  former,  it  makes 
a  large  isosceles  triangle  whose  vertex  is  at  Regulus. 

The  next  considerable  star,  is  5°  N.  of  Regulus, 
marked  q,  situated  in  the  collar;  it  is  of  between 
the  3d  and  4th  magnitudes,  and,  with  Regulus, 
constitutes  the  handle  of  the  sickle.  Those  three 
or  four  stars  of  the  3d  magnitude,  N.  and  W.  of  17, 
arching  round  with  the  neck  of  the  animal,  describe 
the  blade. 

M  Gieba,  marked  y,  is  a  bright  star  of  the  3d 
magnitude,  situated  in  the  shoulder,  4°  in  a  N.  E. 
direction  from  q,  and  may  be  easily  distinguished 
by  its  being  the  brightest  and  middle  one  of  the 
three  stars  lying  in  a  semicircular  form,  curving 
towards  the  west ;  and  it  is  the  first  in  the  blade  of 
the  sickle. 

Adhafera,  marked  £,  is  a  star  of  the  4th  magnitude, 
situated  in  the  neck,  4°  N.  of  M  Gieba,  and  may  be 


104  GEOGRAPHY  OF  THE  HEAVENS. 

known  by  a  very  minute  star  just  below  it.  This 
is  the  second  star  in  the  blade  of  the  sickle. 

Ras  d  Asad,  marked  p,  situated  before  the  ear,  is 
a  star  of  the  3d  magnitude,  6°  W.  of  Adhafera,  and 
is  the  third  in  the  blade  of  the  sickle.  The  next 
star,  s,  of  the  same  magnitude,  situated  in  the  head, 
is  2J°  S.  W.  of  Ras  al  Asad,  and  a  little  within  the 
curve  of  the  sickle.  About  midway  between  these, 
and  a  little  to  the  E.,  is  a  very  small  star,  hardly  visi- 
ble to  the  naked  eye. 

Lambda,  situated  in  the  mouth,  is  a  star  of  the 
4th  magnitude,  3j°  S.  W.  of  «,  and  the  last  in  the 
sickle's  point.  Kappa,  situated  in  the  nose,  is  an- 
other star  of  the  same  magnitude,  and  about  as  far 
from  a,  as  *.  ?  and  *  are  about  5j°  apart,  and  form 
the  longest  side  of  a  triangle,  whose  vertex  is  in  *. 

Zosma,  marked  6,  situated  above  the  back  of  the 
Lion,  is  a  star  of  the  3d  magnitude,  18°  N.  E.  of  Re- 
gulus,and  midway  between  it  and  Coma  Berenices, 
a  fine  cluster  of  small  stars,  18°  N.  E.  of  Zozma. 

Theta,  situated  in  the  tail,  is  another  star  of  the 
3d  magnitude,  5°  directly  S.  of  Zozma,  and  so  nearly 
on  the  same  meridian  that  it  culminates  but  one 
minute  after  it.  This  star  makes  a  right  angled 
triangle  with  Zozma  on  the  N.,  Denebola  on  the  E., 
the  right  angle  being;  at  £. 

Nearly  in  a  straight  line  with  Zozma,  and  £,  and 
south  of  them,  are  three  or  four  smaller  stars,  4°  or 
5°  apart,  which  mark  one  of  the  legs. 

Denebola,  marked  /3,  is  a  bright  star  of  the  2d  mag- 
nitude, in  the  brush  of  the  tail,  10°  S.  E.  of  Zozma, 
and  may  be  distinguished  by  its  great  brilliancy.  It 
is  5°  W.  of  the  equinoctial  colure,  and  comes  to  the 
meridian  one  hour  and  forty-one  minutes  after  Re- 
gulus,  on  the  3d  of  May  ;  when  its  meridian  altitude 
is  the  same  as  the  sun's  at  12  o'clock  the  next  day. 

When  Denebola  is  on  the  meridian,  Regulus  is  seen  25°  VV.  of  it,  and 
Dhad,  in  the  square  of  Ursa  Major,  bears  39°  N.  of  it.  It  forms,  with 


CONSTELLATION  OF  LEO.  105 

these  two,  a  large  right  angled  triangle ;  the  right  angle  being  at  Denebola. 
It  is  so  nearly  on  the  same  meridian  with  Dhad  that  it  culminates  only 
four  minutes  before  it 

Denebola  is  35^°  W.  of  Arcturus,  and  about  the 
same  distance  N.  W.  of  Spica  Virginia,  and  forms, 
with  them,  a  large  equilateral  triangle  on  the  S.  E. 
It  also  forms  with  Arcturus  and  Cor  Caroli  a  similar 
figure,  nearly  as  large  on  the  N.  E.  These  two 
triangles,  being  joined  at  their  base,  constitute  a 
perfect  geometrical  figure  of  the  form  of  a  Rhom- 
bus :  called  by  some,  the  DIAMOND  OF  VIRGO. 

A  line  drawn  from  Denebola  through  Regulus,  and  continued  7°  or  8° 
farther  in  the  same  direction,  will  point  out  |  and  o,  of  the  4th  and  5th 
magnitudes,  situated  in  the  fore  claws,  and  about  3°  apart. 

TELESCOPIC     OBJECTS. 

*  LEOXIS.— A.  R.  =  9  h.  19  m.  53  s.  Dec.  =  -f  9O  45'  0".  A 
very  close  double  star  on  the  Lion's  left  fore  foot.  This  has  long  been  a 
most  difficult  test  object. 

Discovered  by  Herschel,  in  1782,  who  found  the  pos.  ==  1 10°  54',  and 
estimated  the  distance  at  one  quarter  the  diameter  of  the  larger  star  ; 
whose  magnitude  is  6£,  the  smaller  7£. 

Pos.   1530  56'         Dist.  0".970         Epoch  1825.21     Striive. 
178    18  0  .300  1835.33     StrQve. 

194    00  0  ,300  1841.35     Midler. 

In  1842  it  was  seen  as  a  single  star,  by  Miidler. 

The  elements  of  the  orbit  have  been  computed  by  Midler,  who  finds 
a  period  of  82^  years.  By  his  computations  the  stars-were  distant  1''.45, 
their  maxium,  in  1800.  After  a  lapse  of  fifty-two  years  they  will  reach 
their  least  distance  0".2,  which  will  scarcely  be  measurable  in  the  most 
powerful  instruments. 

57  HERSCHEL  I,  LEONIS. — A.  R.  =  9  h.  23  m.  07  s.  Dec.  =  -f- 
22°  12'  1".  A  double  white  nebula  in  the  lower  jaw  of  Leo.  There  is 
a  double  nucleus  with  the  nebulosities  commingling. 

y  LEONIS.— A.  R.  =  10  h.  1 1  m.  08  s.  Dec.  =  -j-  20°  39' 0".  A 
beautiful  double  star  near  the  Lion's  mane.  A  2,  bright  orange ;  B  4, 
greenish  yellow.  This  is  doubtless  a  binary  system,  whose  period  may 
reach  a  thousand  years  !  I  have  repeatedly  examined  this  splendid  ob- 
ject, with  a  power  of  500  ;  the  Cincinnati  refractor  shows  the  disks  of 
both  the  stars  round  and  clear. 

Discovered  by  Herschel,  1782. 

Pos.   103°  22'         Dist.  2".50         Epoch  1831.51     Struve. 


106  GEOGRAPHY   OF   THE   HKAVENS. 

67  P.  X,  LEOXIS.— A.  R.  =  10  h.  17  in.  09  s.  Dec.  =  -j-  9O  35 
2".  A  neat  double  star  on  the  Lion's  right  shoulder.  A  8,  B  9^,  mag- 
nitude. The  measures  indicate  fixity  in  the  components. 

Discovered  by  HerscheL 

.  Pos.   63°  28'         Dist.  4".  00         Epoch  1782.13     HerscheL 
65    54  3  .20  1832.56     Struve. 

49  LEOWIS.— A.  R.  =  10  h.  26  m.  38  s.  Dec.  -f-  9°  28'  5".  A 
close  double  star  under  the  right  shoulder  of  Leo.  A  6,  white  ;  B  9, 
pale  blue. 

Discovered  by  Struve. 

Pos.   161°  09'         Dist.  2". 37         Epoch  3830.76     Struve. 
158    01  2  .50  1838.37     Smyth. 

95  MESSIER,  LEOMS.— A.  R.  =  10  h.  35  m.  31  s.  Dec.  =  12° 
31'  09".  A  white'  nebula  on  the  ribs  of  Leo. 

Discovered  by  Mechain,  1771.  One  degree  east,  and  following  this 
nebula,  is  another,  less  bright,  also  discovered  by  Mechain. 

18  HERSCHEL  I,  LKOTJIS — A.  R.  =  10  h.  39  m.  49  s.  Dec.  =  13° 
28'  0".  A  pair  of  bright  class  nebulae,  with  a  third  faint  one  in  company, 
on  the  belly  of  Leo.  This  region  of  the  heavens  is  filled  with  nebulous 
clouds,  a  part  of  the  great  stream  which  encircles  the  entire  heavens. 

Discovered  by  Herschel  in  1783. 

54  LEONTS.— A.  R.  =  10  h.  46  m.  56  s.    Dec.  =-f-  25°  36'  01'.    A 
double  star  over  Leo's  back.     A  4^,  B  7. 
Discovered  by  Sir  W.  Herschel,  1781. 
Pos.  102°  48'         Dist.  6".  18         Epoch  1830.35     Struve. 

229  P.  X,  LEONIS.— A.  R.  =  10  h  55  m.  44  s.  Dec.  =  -|-  4° 
30'.  A  close  double  star  preceding  the  Lion's  hind  legs.  A  8,  B  8, 
magnitude. 

Discovered  by  Struve,  and  by  him  measured  as  follows : 
Pos.  275°  48'         Dist.  1".076         Epoch  1829.13 

13  HERSCHEL  I,  LEOKTS.— A.  R.  =  10  h.  57  m.  37  s.  Dec.  =  0° 
49'  6".  A  bright  nebula  preceding  the  Lion's  hind  feet.  Discovered  by 
Herschel,  and  one  of  a  vast  number  of  similar  objects  in  this  region. 
IV ear  this  object  Sir  William  examined  more  than  150  square  degrees  of 
diffused  nebulosity,  an  extent  so  vast  as  to  defy  the  powers  of  arithmetic 
to  compute  its  dimensions.  If  we  abandon  the  theory  of  the  existence 
of  chaotic  nebulous  matter,  and  regard  all  these  multitudinous  stains  of 
light  as  consisting  of  myriads  of  suns,  the  extent  of  these  «  island  uni- 
verses "  here  located,  is  almost  infinitely  greater  than  all  that  the  human 
eye  can  grasp  on  the  brightest  night  Herschel  expresses  himself  thus, 
"  The  high  degree  of  rarefaction  of  nebulous  matter,  should  not  be  con- 
sidered an  obstacle  to  the  theory  of  its  finally  being  condensed  into  a  body 
of  the  density  of  the  sun ;  for  supposing  the  nebula  distant  320  billions 
of  miles,  and  its  diameter  equal  to  10',  then  must  its  magnitude  exceed 
that  of  the  sun  more  than  two  trillions  of  times  ! " 


CONSTELLATION  OF  LEO.  107 

What  then  must  be  the  extent  of  a  group  of  objects  covering  150 
square  degrees,  and  so  remote  that  their  millions  of  aggregated  suns  pro- 
duce but  a  barely  perceptible  stain  of  light  on  the  deep  blue  ground  of 
tiie  heavens  1 

239  P.  X,  LEONIS.— A.  R.  =  10  h.  58  m.  17  s.  Dec.  =  -}-  7°  59' 
09".  A  double  star  close  to  the  Lion's  hind  legs.  A  8,  B  1 1  £,  magni- 
tude. It  is  probably  fixed  in  position. 

Pos.  164°  46'         Dist.  =  8",03         Epoch  1833.28     Striive. 

9.  P.  XI,  LEONIS.— A.  R.  =  11  h.  05  m.  17  s.     Dec.  =  -\-  21° 
00'  03".     A  neat  double  star  on  Leo's  loins.     A  7^,  B  7£,  magnitude. 
Discovered  by  Struve. 
Pos.  287°  48'         Dist.  l".052         Epoch  1829.70     Strive. 

66  MESSIER,  LEOXIS.— A.  R.  =  1 1  h.  1 1  m.  48  s.  Dec.  =  -f-  13O 
52'  04".  A  large  elongated  nebula  with  a  bright  nucleus,  preceded  by 
another  of  a  similar  shape. 

Discovered  by  Michain,  1780,  and  registered  No.  66  and  65  Messier. 
A  third  nebula  follows  on  the  same  parallel,  174  seconds  of  time. 

/  LEONIS.— A.  R.  =  1 1  h.  15  m.  35  s.  Dec.  =  -f  1 1°  24'  08".  A 
binary  star  on  the  Lion's  flank,  7°  south-west  of  Denebola,  A  4,  pale 
yellow  ;  B  7£,  light  blue. 

Discovered  by  Str.'  ve 

Pos.  97°  00'         Dist.  2".  30         Epoch  1827.28 

86    00  2  .50  1842.38     Smyth. 

Other  nebulae  and  double  stars  will  be  found  on  the  star  maps. 


SEXTANS. 

THE  SEXTANT,  called  also  URANIA'S  SEXTANT,  is  a 
modern  constellation  that  Hevelius  made  out  of  the 
unformed  stars  of  the  ancients,  which  lay  scattered 
between  the  Lion,  on  the  N.,  and  Hydra,  on  the  S. 

It  contains  forty-one  very  small  stars,  including 
only  one  as  large  as  the  4th  magnitude.  This  is 
situated  very  near  the  equinoctial,  13°  S.  of  Regu- 
lus,  and  comes  to  the  meridian  about  the  same  time 
on  the  6th  of  April.  The  other  stars  in  this  con- 
stellation are  too  small  to  engage  attention.  A 
few  of  the  largest  of  them  may  be  traced  out  fr  *n 
the  map. 


108  GEOGRAPHY  OF  THE  HEAVENS. 

TELESCOPIC     OBJECTS. 

161  P.  IX,  SEXTAWTIS.— A.  R.  =  9  h.  35  ra.  09  s.  Dec.  =  30 
21'  04".  A  double  star  on  the  old  Lion's  leg.  but  included  in  the  nevr 
constellation,  the  Sextant  A  8,  "  yellowish  white  ; "  B  13,  «  blue." 

Pos    1450  00'         Dist    4".00  Epoch  1834.26     Smyth. 

142    20  3.317  1830.24     Struve. . 

163  HERSCHEL  I,  SEXTATTTIS. — A.  R.  =  9  h.  57  m.  16  s.     Dec.= 
—  60  56'  09".     An  elongated  bright  nebula,  on  the  limb  of  the  Sextant. 
Discovered  by  Herschel,  1787. 

4  HERSCHEL  I,  SEXTANTIS.— A.  R.  =  10  h.  05  m.  58  s.  Dec.  = 
-f-  40  15'  01".  A  bright  round  nebula  on  the  frame  of  the  Sextant,  fol- 
lowed by  another  at  the  distance  of  twenty-nine  seconds  of  time. 

Discovered  by  Herschel,  1783;  who,  however,  overlooked  the  follow- 
ing one,  which  was  subsequently  discovered  by  his  son. 

35  SEXTANTIS.— A.  R.  =  10  h.  35  m.  02  s.     Dec.  =  -j-  5°  35'  02". 
A  double  star  on  the  north  extreme  of  the  limb.     A  7,  B  8. 
Pos.  240°  47'         Dist.  6".75         Epoch  1825.20     Struve. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    X. 

HYDRA — THE  WATER  SERPENT. 
POCULA — THE  CUP. 
FELIS— THE  CAT. 
THE  COMPASS. 

Favorably  situated  for  examination  in  March,  April 
and  May. 

HYDRA    AND    THE     CUP. 

HYDRA,  THE  WATER  SERPENT,  is  an  extensive  con- 
stellation, winding  from  E.  to  W.  in  a  serpentine 
direction,  over  a  space  of  more  than  one  hundred 
degrees  in  length.  It  lies  south  of  Cancer,  Leo,  and 
Virgo,  and  reaches  almost  from  Canis  Minor  to 
Libra.  It  contains  sixty  stars,  including  one  of 


CONSTELLATION  OF   HYDRA.  109 

the  2d  magnitude,  three  of  the  3d,  and  twelve  of 
the  4th. 

Aiphard,  or  Cor  Hydros,  marked  a,  in  the  heart,  is 
a  lone  star  of  the  2d  magnitude,  23°  S.  S.  W.  of 
Regulus,  and  comes  to  the  meridian  at  the  same 
time  with  *,in  the  point  of  the  sickle,  about  twenty 
minutes  before  9  o'clock  on  the  1st  of  April.  There 
is  no  other  considerable  star  near  it,  for  which  it 
can  be  mistaken.  An  imaginary  line  drawn  from 
y  Leonis  through  Regulus,  will  point  out  Cor  Hydrse, 
at  the  distance  of  23°. 

The  head  of  Hydra  may  be  distinguished  by  means 
of  four  stars  of  the  4th  magnitude,  2^°  and  4°  apart, 
and  forming  a  rhomboidal  figure.  The  three  tipper 
stars  in  this  cluster  form  a  small  arch,  and  may  be 
known  by  two  very  small  stars  just  below  the 
middle  one,  making  with  it  a  very  small  triangle. 
The  three  western  stars  in  the  head,  also  make  a 
beautiful  little  triangle.  The  easten  star  in  this 
group,  marked  £,  is  about  6°  directly  S.  of  Acubens, 
and  culminates  at  the  same  time. 

When  Alphard  is  on  the  meridian,  Alkes,  marked 
a,  of  the  4th  magnitude,  situated  in  the  bottom  of 
the  Cup,  may  be  seen  24°  S.  E.  of  ify  and  is  dis- 
tinguished by  its  forming  an  equilateral  triangle 
with  j3  and  y,  stars  of  the  same  magnitude,  6°  S. 
and  E.  of  it.  Alkes  is  common  both  to  Hydra  and 
the  Cup.  £,  on  the  S.,  is  in  Hydra,  and  y,  on  the  N. 
E.,  is  near  the  middle  of  the  Cup.  A  line  drawn 
from  Zozma,  through  £  Leonis,  and  continued  38^° 
directly  S.  will  reach  j3 ;  it  is  therefore  on  the  same 
meridian,  and  will  culminate  at  the  same  time  on 
the  23d  of  April. 

The  Cup  itself,  called  also  the  Crater,  may  be 
easily  distinguished  by  means  of  six  stars  of  the  4th 
magnitude,  forming  a  beautiful  crescent,  or  semi- 
circle, opening  to  the  W.  The  center  of  this  group 
is  about  15°  below  the  equinoctial,  and  directly  S. 
K  • 


110        GEOGRAPHY  OF  THE  HEAVENS. 

of  the  hinder  feet  of  Leo.  The  crescent  form  of 
the  stars  in  the  Cup  is  so  striking  and  well  defined, 
when  the  moon  is  absent,  that  no  other  description 
is  necessary  to  point  them  out.  Its  center  comes  to 
the  meridian  about  two  hours  after  Alphard,  on  the 
same  evening ;  and  consequently,  it  culminates  at 
9  o'clock,  one  month  after  Alphard  does.  The  re- 
mainder of  the  stars  in  this  constellation  may  be 
easily  traced  by  aid  of  the  map. 

When  the  head  of  Hydra  is  on  the  meridian,  its 
other  extremity  is  many  degrees  below  the  horizon, 
so  that  its  whole  length  cannot  be  traced  out  in 
the  heavens  until  its  center,  or  the  Cup,  is  on  the 
meridian. 

"  Near  the  equator  rolls 

The  sparkling  Hydra,  proudly  eminent 
To  drink  the  Galaxy's  refulgent  sea ; 
Nearly  a  fourth  of  the  encirling  curve 
Which  girds  the  ecliptic,  his  vast  folds  involve  ; 
Yet  ten  the  number  of  his  stars  diffused 
O'er  the  long  track  of  his  enormous  spires : 
Chief  beams  his  heart,  sure  of  the  second  rank, 
But  emulous  to  gain  the  first." — Eudosia. 

TELESCOPIC     OBJECTS. 

108  P.  VIII,  HTDRJE.— A.  R.  =  8  h.  27  m.  20  s.  Dec.  =  -f-  7<> 
10'  05".  A  double  star  between  the  head  of  Hydra  and  Cancer.  A  6, 
"  pale  yellow ;  "  B  7£,  "  rose  tint." 

Discovered  by  Herschel. 

Pos.  25045'         Dist.  10".  33         Epoch  1832.95     Striive. 

17  HYDROS.— A.  R.  =  8  h.  47  m.  39  s.  Dec.  =  —  7°  21'  08".  A 
close  double  star  between  the  Unicorn's  tail  and  Hydra's  heart.  A  and 
B  7  magnitude. 

Discovered  by  Herschel. 

Pos.  358°  50'         Dist.  4".33-        Epoch  1831.59     Struve. 

27  HERSCHEI  IV,  HYDROS.— A.  R.  =  10  h.  17  m.  01  s.     Dec.  = 
—  17°  50'  06".     A  planetary  nebula  hi  the  middle  of  Hydra's  body. 
Discovered  by  Herschel,  1785. 

OL  CRATERIS.— A.  R.  =  10  h.  52  m.  00  s.  Dec.  =  —  17°  26'  09". 
A  star  with  two  distant  companions  on  the  base  of  the  Cup.  These  are 
remarkable  for  then-  color.  A  4,  orange ;  B  8,  blood  red  ;  C  9,  pale  blue. 

Difference  between  A  and  B  42".  1 
"  «        A  and  C    4  .9 


CONSTELLATION  OF  HYDRA.  Ill 

39  P.  XI,  CRATERIS.— A.  R  =  11  h.  11  m.  38  s.    Dec.  =  —  06° 

01'  04".     A  small  double  star  between  the  Cup  and  the  Lion's  hind  feet 
A  8£,  B  9,  magnitude. 

Discovered  by  Struve. 

Pos.  3140  00'         Dist.  7".65         Epoch  1830.23     Struve. 

y  CHATEHIS.— A.  R.  =  11  h.  16  m.  54  s.    Dec.  =  —  16°  48'  03". 
A  close  double  star  in  the  center  of  the  goblet.     A  4,  B  14,  magnitude. 
Discovered  by  Herschel. 
Pos.  102°05'         Dist  3".00         Epoch  1838.26     Smyth. 

1 7  CRATERIS.— A.  R.  =  1 1  h.  24  m.  2 1  s.     Dec.  =  —  28°  23'  00". 
A  double  star  in  the  boundary  of  the  Cup.     A  5 £,  B  7,  magnitude. 
Discovered  by  Herschel,  1783. 
Pos.  207008'         Dist  10".01         Epoch  1833.21     Smyth. 


CONSTELLATION  OF  VIRGO.  113 


CHAPTER  III. 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XI. 

VIRGO — THE  VIRGIN. 
CORVUS — THE  CROW. 

Favorably  situated  for  examination  in  April,  May 
and  June. 

VIRGO. 

THE  VIRGIN. — This  is  the  sixth  sign,  and  seventh 
constellation  in  the  ecliptic.  It  is  situated  next 
east  of  Leo,  and  about  midway  between  Coma 
Berenices  on  the  N.  and  Corvus  on  the  S.  It  oc- 
cupies a  considerable  space  in  the  heavens,  and 
contains,  according  to  Flamsted,  one  hundred  and 
ten  stars,  including  one  of  the  1st.,  six  of  the  3d,  and 
ten  of  the  4th  magnitudes.  Its  mean  declination  is 
5°  N.,  and  its  mean  right  ascension  is  195°.  Its 
center  is  therefore  on  the  meridian  about  the  23d 
of  May. 

The  sun  enters  the  sign  Virgo,  on  the  23d  of  August,  but  does  not 
enter  the  constellation  before  the  15th  of  September.  When  the  sun 
is  in  this  sign,  the  earth  is  in  Pisces ;  and  vice  versa. 

Spica  Virginis,  marked  »,  in  the  ear  of  corn  which 
the  Virgin  holds  in  her  left  hand,  is  the  most  brilliant 
star  in  this  constellation,  and  situated  nearly  15°  E. 
N.  E.  of  Algorab,  marked  »,  in  the  Crow,  about  35° 
S.  E.  of  Denebola,  and  nearly  as  far  S.  S.  W.  of 
Arcturus — three  very  brilliant  stars  of  the  1st  mag- 
nitude, that  form  a  large  equilateral  triangle,  point- 


114  GEOGRAPHY   OF   THE   HEAVENS. 

ing  to  the  S.  Arcturus  and  Denebola,  marked  0, 
are  also  the  base  of  a  similar  triangle  on  the  north, 
terminating  in  Cor  Caroli,  which,  joined  to  the 
former,  constitutes  the  Diamond  of  Virgo.  The 
length  of  this  figure,  from  Cor  Caroli  on  the  north, 
to  Spica  Virginis  on  the  south,  is  50°.  Its  breadth, 
or  shorter  diameter,  extending  from  Arcturus  on  the 
east,  to  Denebola  on  the  west,  is  35^°.  Spica  may 
otherwise  be  known  by  its  solitary  splendor,  there 
being  no  visible  star  near  it,  except  one  of  the  5th 
magnitude,  situated  about  1°  below  it.  on  the  left. 

The  position  of  this  star  in  the  heavens,  has  been 
determined  with  great  exactness  for  the  benefit  of 
navigators.  It  is  one  of  the  stars  from  which  the 
moon's  distance  is  taken  for  determining  the  longi- 
tude at  sea.  Its  situation  is  highly  favorable  for 
this  purpose,  as  it  lies  within  the  moon's  path,  and 
little  more  than  2°  below  the  earth's  orbit. 

Its  right  ascension  being  199°,  it  will  come  to  our 
meridian  at  9  o'clock  about  the  28th  of  May,  in  that 
point  of  the  heavens  where  the  sun  is  at  noon  about 
the  20th  of  October. 

Vindemiatrix,  marked  «,  is  a  star  of  the  3d  magnitude,  in  the  right  arm, 
or  northern  wing  of  Virgo,  and  is  situated  nearly  in  a  straight  line  with, 
and  midway  between  Coma  Berenices,  and  Spica  Virginis.  It  is  19^° 
6.  W.  of  Arcturus,  and  about  the  same  distance  S.  E.  of  Coma  Berenices, 
and  forms  with  these  two  a  large  triangle,  pointing  to  the  south.  It  bears 
also  18°  S.  S.  E.  of  Denebola,  and  comes  to  the  meridian  about  twenty- 
three  minutes  before  Spica  Virginis. 

Zeta,  is  a  star1  of  the  3d  magnitude,  11  £°  N.  of  Spica,  and  very  near 
the  equinoctial.  Gamma,  situated  near  the  left  side,  is  also  a  star  of  the 
3d  magnitude,  and  very  near  the  equinoctial.  It  is  13°  due  west  of  £.  with 
which  and  Spica  it  forms  a  handsome  triangle.  Eta,  is  a  star  of  the  3d 
magnitude,  in  the  southern  wing,  5°  W.  of  y,  and  but  2£°  E.  of  the 
autumnal  equinox. 

Beta,  called  also  Zavijava,  is  a  star  of  the  3d  magnitude,  in  the  shoul- 
der of  the  wing,  7%°  W.  of  «,  with  which  and  y,  it  forms  a  line  near  the 
earth's  orbit,  and  parallel  to  it.  &  „,  y  and  Spica,  form  the  lower  and 
longer  side  of  a  large  spherical  triangle,  whose  vertex  is  in  yg.  The  other 
stars  in  this  figure  may  be  easily  traced  by  means  of  the  map.  About  1 3° 
E.  of  Spica,  there  are  two  stars  of  the  4th  magnitude,  3°  apart,  which  mark 
the  foot  of  Virgo.  These  two  stars  are  on  nearly  the  same  meridian  with 


CONSTELLATION  OF  VIRGO.  115 

Arcturus,  and  culminate  nearly  at  the  same  time.  The  lower  one  marked 
Lambda,  is  on  the  south,  and  but  8°  W.  of  the  principal  star  in  Libra. 
Several  other  stars  of  the  3d  magnitude  lie  scattered  about  in  this  con- 
stellation, and  may  be  traced  out  by  the  map. 

"  Her  lovely  tresses  glow  with  starry  light ; 
Stars  ornament  the  bracelet  on  her  hand  ; 
Her  vest  in  ample  fold,  glitters  with  stars  : 
Beneath  her  snowy  feet  they  shine ;  her  eyes 
Lighten,  all  glorious,  with  the  heavenly  rays, 
But  first  the  star  which  crowns  the  golden  sheaf." 

^  HISTORY. — The  famous  zodiac  of  Dendera,  as  we  have  already  noticed, 
commences  with  the  sign  Leo  ;  but  another  zodiac,  discovered  among  the 
ruins  at  Estne,  in  Egypt,  commences  with  Virgo ;  and  from  this  circum- 
stance, some  have  argued,  that  the  regular  precession  of  the  equinoxes 
established  a  date  to  this  at  least  2000  years  older  than  that  at  Dendera. 
The  discoveries  of  Champollion,  however,  render  it  probable  that  this 
ancient  relic  of  astrology  at  Estne  was  erected  during  the  reign  of  the 
Emperor  Claudius,  and  consequently  did  not  precede  the  one  at  Dendera 
<>pore  than  fourteefi  years. 

Of  this,  however,  we  may  be  certain :  the  autumnal  equinox  now  cor- 
responds with  the  first  degree  of  Virgo  ;  and,  consequently,  if  we  find  a 
zodiac  in  which  the  summer  solstice  was  placed  where  the  autumnal 
equinox  now  is,  that  zodiac  carries  us  back  90°  on  the  ecliptic ;  this 
divided  by  the  annual  precession  of  50£",  must  fix  the  date  at  about  6450 
years  ago.  This  computation,  according  to  the  chronology  of  the  Sacred 
writings,  carries  us  back  to  the  earliest  ages  of  the  human  species  on 
earth,  and  proves,  at  least,  that  astronomy  was  among  the  first  studies  of 
mankind.  The  most  rational  way  of  accounting  for  this  zodiac,  says 
Jamieson,  is  to  ascribe  it  to  the  family  of  Noah  ;  or  perhaps  to  the  patri- 
arch himself,  who  constructed  it  for  the  benefit  of  those  who  should  live 
after  the  deluge,  and  who  preserved  it  as  a  monument  to  perpetuate  tLe 
actual  state  of  the  heavens  immediately  subsequent  to  the.  creation. 


TELESCOPIC     OBJECTS. 

A  NKBUOA.— A.  R.  =  12h.  06  m.  01  s.  Dec.  =  -f  15°  47'  02". 
This  nebula  is  situated  between  Virgo's  right  wing  and  Leo's  tail. 

Discovered  by  Messier,  1781,  and  described  by  him  as  "  a  nebula  with- 
out a  star,  with  an  extremely  faint  light. 

A  Loxe  PALE-WHITE  NEBULA.— A.  R.  =  12  h.  07  m.  37  s.  Dec. 
4-  HO  02'  08".  On  the  upper  part  of  Virgo's  left  wing.  Described  in 
the  Bedford  Catalogue  as  "  a  very  curious  object,  resembling  a  weaver's 
shuttle,  and  lying  across  the  parallel.  The  upper  branch  is  the  faintest, 
and  exhibits  a  palpable  nucleus." 

Discovered  by  Herschel,  1783. 

A  LARGE  NEBULA.— A.  R.  =  12  h.  13  m.  45  s.     Dec.  =  -f  05° 


116  GEOGRAPHY  OF  THE  HEAVENS. 

21' 06".     This  nebula  is  situated  between  the  Virgin's  shoulders.     Her- 
schel  reports  it  to  have  two  neuclei  about  90"  apart. 
Discovered  by  Messier,  1799. 

1?  VIRGINS.— A.  R.  =  12  h.  14  m.  24  s.    Dec.  —  06O  1 1'  08". 
A  double  star  between  the  shoulders  of  Virgo.      A  6,  B  9,  magnitude. 
Pos.  336045'         Dist  19".32         Epoch  1829.26    Struve. 
The  components  appear  to  be  stationary. 

A  ROUND  NEBULA.— A.  R.  =  12  h.  14  m.  52  s  Dec.  =  -}-  16° 
42'  06".  It  appears  off  the  upper  part  of  the  Virgin's  left  wing. 

Discovered  by  Mechain,  1781. 

It  is  one  of  a  multitude  of  nebulous  masses  forming  a  wonderful  zone, 
and  passing  round  the  heavens  in  a  direction  nearly  perpendicular  to  the 
Milky  Way.  The  discovery  of  this  great  stratum,  is  the  result  of  the 
unwearied  zeal  and  perseverance  of  Sir  William  Herschel. 

A  BRIGHT  NEBULA.— A.  R.  =  12  h.  21  m.  36  s.     Dec.  -f-  08°  52' 
09".     This  nebula  is  situated  on  Virgo's  left  shoulder. 
Discovered  by  Orioni,  1771. 

A  LONG  ELLIPTICAL  NEBULA — A.  R.  =  12  h.  23  m  54  s.  Dec.  = 
-f-  15°  18'  05".  It  appears  on  the  outer  side  of  Virgo's  left  wing.  In  a 
zone  three  degrees  square  a  large  number  of  nebulae  are  found,  whose 
relative  positions  are  exhibited  in  the  diagram  marked  nebulae  in  Virgo. 

y  VIRGINIS.— A.  R.  =  12  h.  33  m.  33  s.  Dec.  =  —  00°  34'  03". 
A  remarkable  binary  star,  on  the  Virgin's  right  side.  A  4,  B  4,  magni- 
tude. In  consequence  of  some  very  early  observations,  by  Bradly,  Pound, 
Cassini,  and  Mayer,  it  was  thought  that  this  star  presented  an  admirable 
opportunity  of  testing  the  influence  of  gravitation  among  these  remote 
objects.  As  early  as  1718,  the  positions  of  the  components  seem  to 
have  been  approximately  obtained.  Measures  were  again  made  in  1720, 
1756,  and  by  Sir  W.  Herschel  in  1780.  These,  combined  with  modem 
observations,  furnished  the  data  for  the  computation  of  the  elements  of  the 
orbits,  described  by  these  two  suns  about  their  common  center  of  gravity. 
From  the  earliest  period  of  observation,  the  distance  between  the  two 
stars  composing  y  Virginia,  had  been  on  the  decrease,  while  the  angular 
velocity  was  rapidly  increasing ;  following,  in  this  respect,  the  analogy  of 
the  planets  and  comets,  whose  angular  velocity  rapidly  increases  as  their 
distance  from  the  sun  decreases.  Sir  John  Herschel  made  the  first  effort 
at  a  determination  of  the  elements  of  the  orbit,  and  found  a  period  of 
513.28  years  by  the  first  computed  elements,  and  of  628.90  years  by  the 
second  set  of  elements.  These  results  were  greatly  in  error,  owing  to 
the  fact,  as  Sir  John  Herschel  says,  to  the  use  of  Bradly's  observations 
of  1718.  In  the  meantime  M.  Mildler,  of  Dorpat,  had  shown  that  the 
periodic  time  could  not  well  exceed  1 57  years,  a  result  finally  reached  by 
Herschel  himself. 

After  much  laborious  calculation,  M.  Miidler  reached  the  conclusion 
that  the  perihelion  or  pereaster  passage  occurred  1836.31,  and  that  the 


Pos.  H59°  53'  0(i" 

Dist.  02".417 

357  43  04 

02  .556 

355  55  06 

02  .689 

354  1H  03 

02  .816 

352  39  06 

02  .9:59 

351  13  06 

0:5  .057 

349  53  05 

03  .170 

CONSTELLATION  OF  VIRGO.  117 

periodic  time  was  145.409  years.     With  his  last  set  of  elements,  he  has 
computed  an  ephemeris  of  this  system,  from  which  we  copy  as  follows: 

Epoch  1847 
1848 
1849 
1850 
1851 
1852 
1853 

During  a  part  of  the  year  1836,  the  star  was  seen  perfectly  round,  even 
in  the  most  powerful  instruments.  Objects  which  had  been  so  widely 
separated,  when  first  discovered,  were  now  so  placed  as  that  the  one 
eclipsed  the  other.  Towards  the  close  of  1836,  the  hidden  star  began  to 
emerge,  and  this  double  object  was  seen  elongated.  At  the  beginning 
of  I  £37,  the  best  telescopes  again  saw  the  two  stars  separate  and  distinct. 
From  that  time,  to  the  present,  the  distance  has  been  on  the  increase, 
while  the  angular  velocity  has  been  regularly  diminishing.  My  own 
observations  show  the  ephemeris  computed  by  Mildler,  to  be  pretty  ac- 
curate, but  even  yet  considerable  discordance  exists  between  observation 
and  computation,  showing  that  more  accurate  data  are  yet  wanted  to 
complete  this  most  delicate  and  difficult  investigation 
A  few  measures  are  here  given. 
Pos.  =  319007'  Dist.  07".49  Epoch  172031  CassinL 

350    04  ---  1781.89     Herschel  I. 

285    04  02  .80  182200     Strive. 

262     10  01  .58  183059     Bessel. 

245    32  01  .05  1833.:<7     Strive. 

077    55  00  .58  1837.41     Struve. 

020     11  01  .7-<  1841.44     Midler. 

Oil     06  01   .90  1843.33     Smyth. 

357    28  03  .09  1847.60     MitcheL 

By  a  comparison  of  the  last  observations  with  the  ephemeris,  it  will  be 
seen  that  the  angular  velocity  is  greater  than  predicted,  as  is  also  the  in- 
crease of  distance  between  the  components. 

6  VIIUJTNIS.— A.  R.  =  13  h.  01  m.  40  s.  Dec.  =  —  04°  41'  00". 
A  coarse  triple  star  on  the  lower  part  of  the  Virgin's  southern  wing.  A 
4^,  B  9,  (J.  10,  magnitude. 

Pos.  A  B  344002'         Dist.  07". 02         Epoch  1 837.07  ?Q       , 
A  C  295    00  65  .00  1831.155       y' 

A  CLOSE  BIXATIY  STAR. — A.  R.  =  13  h.  26  m.  07  s.  Dec.  =  -{- 
00°  30'  04".  This  star  is  situated  on  Virgo's  lower  garment.  A  8,  B 
9,  magnitude. 

Discovered  by  Stri'ive,  1825. 

Poe.  100  00'         Dist.  01".600         Epoch  1825.37     Struve. 
24    08  01  .590  1834.38     Struve. 

36    02  01  .747  1841.37     Midler. 

The  period  of  revolution  is,  probably,  not  far  from  230  years. 

81  VIRGINIS.— A.  R.  =  13  h.  29  m.  13  s.    Dec.  =  —  07°  03'  02". 


118  GEOGRAPHY   OF   THE  HEAVENS. 

A  close  double  star  on  the  right  side  of  the  lower  garment  of  the  Virgin. 
Suspected  of  slow  retrogradation. 

Pos.  41°  07'         Dist.  02".82         Epoch  1841.39     Mudler. 

84  VIRGINS A.  R.  =  13  h.  35  m  02  s.     Dec.  =  -}-  04°  21'  00". 

A  close  double  star  on  the  tip  of  Virgo's  left  wing.     A  »i,  B  9,  magnitude. 
Pos.  233°04'         Dist.  03".5     .      Epoch  1839.37     Smyth. 
231     05  03  .48  1847.06     Mitchel. 

9  VIRGINIS.— A.  R.  =  14  h.  19  m.  58  s.  Dec.  =  —  Olc  30'  04". 
A  delicate  double  star  in  the  corner  of  Virgo's  skirt.  A  5,  yellow ;  B 
13,  blue. 

Discovered  by  Strive,  1829. 

Pos.  108°  32'         Dist.  03".73         Epoch  1829.71     Struve. 

Other  double  stars  and  nebulae  will  be  found  on  the  chart. 

A  DOUBLE  NEBULA.— A.  R.  =  12  h.  35  m.  33  s.     Dec.  =  -f-  12° 

26'  0 1".  This  nebula  is  situated  in  the  center  of  Virgo's  left  wing,  with 
two  or  three  smaller  ones  in  the  immediate  vincinity.  In  this  object  we 
find  some  support  to  the  celebrated  nebular  theory,  which  supposes  the  sun 
and  stars  to  have  been  formed  from  the  condensation  of  nebulous  fluids. 
The  object  before  us  suggests  the  chaotic  state  of  a  binary  star,  and  possi- 
bly these  two  shadowy  objects  are  performing,  even  now,  a  revolution 
round  each  other.  Abandoning  this  theory,  and  having  recourse  to  the 
idea  that  these  dim  stains  are  mighty  universes  of  shining  stars,  here  we 
have  two  such  so  located  as  possibly  to  be  mutually  operating  upon  each 
other.  Should  actual  physical  connection  exist,  and  one  of  these  mighty 
systems  be  actually  sweeping  round  the  other,  what  a  stupendous  period 
must  mark  the  cycle  of  these  "  island  universes."  By  such  periods  we 
might  even  reckon  the  hours  of  eternity  itself !  " 


CORVUS. 

THE  CROW. — This  small  constellation  is  situated 
on  the  eastern  part  of  Hydra,  15°  E.  of  the  Cup,  and 
is  on  the  same  meridian  with  Coma  Berenices,  but 
as  far  S.  of  the  equinoctial  as  Coma  Berenices  is  N. 
of  it.  It  therefore  culminates  at  the  same  time,  on 
the  12th  of  May.  It  contains  nine  visible  stars, 
including  three  of  the  3d  magnitude,  and  two  of 
the  4th. 

This  constellation  is  readily  distinguished  by 
means  of  three  stars  of  the  3d  magnitude,  and  one 
of  the  4th,  forming  a  trapezium  or  irregular  square, 


CONSTELLATION   OF  CORVUS.  119 

the  two  upper  ones  being  about  3-z°  apart,  and  the 
two  lower  ones  6°  apart. 

The  brightest  of  the  two  upper  stars,  on  the  left, 
is  called  Algorab,  marked  a,  and  is  situated  in  the  E. 
wing  of  the  Crow  ;  it  has  nearly  the  same  declina- 
tion S.  that  the  Dog-star  has,  and  is  on  the  meridian 
about  the  13th  of  May.  It  is  21^°  E.  of  Alkes  in 
the  Cup,  14^°  S.  W.  of  Spica  Virginis,  a  brilliant 
star  of  the  1st  magnitude,  to  be  described  in  the  next 
chapter. 

Beta,  on  the  back  of  Hydra  and  in  the  foot  of  the 
Crow  is  a  star  of  the  3d  magnitude,  nearly  7°  S. 
of  Algorab.  It  is  the  brightest  of  the  two  lower 
stars,  and  on  the  left.  The  right  hand  lower  one 
is  a  star  of  the  4th  magnitude,  situated  in  the  neck, 
marked  Epsilon,  about  6°  W.  of  j3,  and  may  be 
known  by  a  star  of  the  same  magnitude  situated 
2°  below  it,  in  the  eye,  and  called  Al  Chiba.  t  is 
21  J°  S.  of  the  vernal  equinox,  and  if  a  meridian 
should  be  drawn  from  the  pole  through  Megrez,  and 
produced  to  «  Corvi,  it  would  mark  the  equinoctial 
colure. 

Gamma  in  the  W.  wing,  is  a  star  of  the  3d  mag- 
nitude, 3^°  W.  of  Algorab,  and  is  the  upper  right 
hand  one  in  the  square.  It  is  but  1°  E.  of  the  equi- 
noctial colure. 

10°  E.  of  j3  is  a  star  of  the  3d  magnitude,  in  the 
tail  of  Hydra,  marked  y ;  these  two.  with  Algorab, 
form  nearly  a  right  angled  triangle,  the  right  angle 
being  at  |3. 

TELESCOPIC     OBJECTS, 

<T  CORVI.— A.  R.  =  12  h.  2 1  m.  35  s.     Dec.  =  —  15°  34'  04".     A 
Qne  double  star  on  the  Raven's  right  wing.     A  3,  B  8|  magnitude. 
Discovered  by  Herschel,  1782. 
Pos.  210°  5i'         Dist.  23".o         Epoch  1831.34     Smyth. 


120  GEOGRAPHY  OF  THE  HEAVENS. 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XII. 

URSA  MAJOR — THE  GREAT  BEAR. 

Favorably  situated  for  examination  in  May,  Jane. 
July,  August  and  September. 

URSA     MAJOR. 

THE  GREAT  BEAR. — This  great  constellation  is 
situated  between  Ursa  Minor  on  the  north,  and  Leo 
Minor  on  the  south.  It  is  one  of  the  most  noted 
and  conspicuous  in  the  northern  hemisphere.  It 
has  been  an  object  of  universal  observation  in  all 
ages  of  the  world.  The  priests  of  Belus,  and  the 
Magi  of  Persia ;  the  shepherds  of  Chaldea,  and  the 
Phoenician  navigators,  seem  to  have  been  equally 
struck  with  its  peculiar  outlines.  And  it  is  some- 
what remarkable  that  a  remote  nation  of  American 
aborigines,  the  Iroquois,  and  the  earliest  Arabs  of 
Asia,  should  have  given  to  the  very  same  constella- 
tion the  name  of  "  Great  Bear,"  when  there  had 
probably  never  been  any  communication  between 
them ;  and  when  the  name  itself  is  so  perfectly 
arbitrary,  there  being  no  resemblance  whatever  to 
a  bear,  or  to  any  other  animal. 

It  is  readily  distinguished  from  all  others  by 
means  of  a  remarkable  cluster  of  seven  bright 
stars,  forming  what  is  familiarly  termed  the  Dipper, 
or  Ladle.  In  some  parts  of  England  it  is  called 
"  Charles's  Wain,"  or  wagon,  from  its  fancied  re- 
semblance to  a  wagon  drawn  by  three  horses  in  a 
line.  Others  call  it  the  Plow.  The  cluster,  how- 
ever, is  more  frequently  put  for  the  whole  constella- 
tion, and  called,  simply,  the  Great  Bear.  But  we 
see  no  reason  to  reject  the  very  appropriate  appel- 


CONSTELLATION  OF  URSA  MAJOR.       121 

lation  of  the  shepherds,  for  the  resemblance  is 
certainly  in  favor  of  the  Dipper:  the  four  stars  in 
the  square  forming  the  bowl,  and  the  other  three, 
the  handle. 

When  the  Dipper  is  on  the  meridian,  above  the 
pole,  the  bottom  lies  towards  us,  with  the  handle 
on  the  right. 

Benetnasch,  marked  ^  is  a  bright  star  of  the  2d 
magnitude,  and  is  the  first  in  the  handle.  The 
second,  or  middle  star  in  the  handle,  is  Mizar, 
marked  f,  7°  distant  from  Benetnasch.  It  may  be 
known  by  means  of  a  very  minute  star  almost 
touching  it,  called  Alcor,  which  appears  to  be  double 
when  seen  through  a  telescope,  and  of  a  silver 
white.  The  third  star  in  the  handle  is  called  Alioth, 
marked  «,  and  is  about  4j°  W.  of  Mizar.  Alioth  is 
very  nearly  opposite  Shedir  in  Cassiopeia,  and  at 
an  equal  distance  from  the  pole.  Benetnasch, 
Mizar,  and  Alioth,  constitute  the  handle,  while  the 
next  four  in  the  square  form  the  bowl  of  the  Dipper. 

Five  and  a  half  degrees  W.  of  Alioth  is  the  first 
star  in  the  top  of  the  Dipper,  at  the  junction  of  the 
handle,  called  Megrez,  and  marked  8 ;  it  is  the 
smallest  and  middle  one  of  the  cluster,  and  is  used 
in  various  observations  both  on  sea  and  land,  for 
important  purposes.  At  the  distance  of  4^°  S.  W. 
of  Megrez,  is  Phad,  marked  y,  the  first  star  in  that 
part  of  the  bottom,  which  is  next  the  handle. 

The  stars  in  this  cluster  are  so  well  known,  and  may  be  so  easily  de- 
scribed without  reference  to  their  relative  bearings,  that  they  would  rather 
confuse  than  assist  the  student,  were  they  given  with  ever  so  much  ac- 
curacy. The  several  bearings  for  this  cluster  were  taken  when  Megrez 
was  on  the  meridian,  and  will  not  apply  at  any  other  time,  though  their 
respective  distances  will  remain  the  same. 

At  the  distance  of  8°  W.  of  Phad,  is  the  western- 
most star  in  the  bottom  of  the  Dipper,  called  Mcrak, 
marked  p.     The  bright  star  5°  N.  of  it,  towards  the 
pole  is  called  Dubhe,  and  marked  a ;  but  these  two, 
L 


122        GEOGRAPHY  OF  THE  HEAVENS. 

Merak  and  Dubhe,  are,  by  common  consent,  called 
the  Pointers,  because  they  always  point  towards  the 
pole  ;  for,  let  the  line  which  joins  them  be  continued 
in  the  same  direction  28J0  farther,  it  will  just  reach 
the  north  pole. 

The  names,  positions,  and  relative  distances  of 
the  stars  in  this  cluster,  should  be  well  remembered, 
as  they  will  be  frequently  adverted  to.  The  dis- 
tance of  Dubhe,  or  the  Pointer  nearest  to  the  north 
pole,  is  28|-°.  The  distance  between  the  two  upper 
stars  in  the  Dipper  is  10°  ;  between  the  two  lower 
ones  8°  :  the  distance  from  the  brim  to  the  bottom 
next  the  handle,  is  4^°  ;  between  Megrez  and  Alioth 
is  5j° ;  between  Alioth  and  Mizar  4j°,  and  between 
Mizar  and  Benetnasch,  7°. 

The  reason  why  it  is  important  to  have  these  distances  clearly  settled 
in  the  mind  is,  that  these  stars,  being  always  in  view,  and  more  familiar 
than  any  other,  the  student  will  never  fail  to  have  a  standard  measure 
before  him,  which  the  eye  can  easily  make  use  of  in  determining  the 
distances  between  other  stars. 

The  position  of  Megrez  in  Ursa  Major,  and  of 
Caph  in  Cassiopeia,  is  somewhat  remarkable.  They 
are  both  in  the  equinoctial  colure,  almost  exactly 
opposite  each  other,  and  equally  distant  from  the 
pole.  Caph  is  in  the  colure,  which  passes  through 
the  vernal  equinox,  and  Megrez  is  in  that  which 
passes  through  the  autumnal  equinox.  The  latter 
passes  the  meridian  at  9  o'clock,  on  the  10th  of 
May,  and  the  former  just  six  months  afterwards,  at 
the  same  hour,  on  the  10th  of  November. 

Psi,  in  the  left  leg  of  Ursa  Major,  is  a  star  of  the 
3d  magnitude,  in  a  straight  line  with  Megrez  and 
Phad,  distant  from  the  later  12j°.  A  little  out  of 
the  same  line,  3°  farther,  is  another  star  of  the  5th 
magnitude,  marked  Omega,  which  may  be  dis- 
tinguished from  4,,  from  its  forming  a  straight  line 
with  the  two  Pointers. 

The   right   fore  paw,  and  hinder  one,  are  dis- 


CONSTELLATION  OF  URSA  MAJOR,  123 

tinguished  by  two  stars  of  the  4th  magnitude,  be- 
tween 1°  and  2°  apart.  The  two  stars  of  the  left 
hind  paw  are  of  the  3d  magnitude.  These  three 
duplicate  stars  are  nearly  in  a  right  line,  20°  S.  of, 
and  in  a  direction  nearly  parallel  with,  Phad  and 
Dubhe,  and  are  the  only  stars  in  this  constellation 
that  ever  set  in  this  latitude. 

There  are  few  other  stars  of  equal  brightness 
with  those  just  described,  but  amidst  the  more 
splendid  and  interesting  group  with  which  they 
are  clustered,  they  seldom  engage  our  observation. 

The  whole  number  of  visible  stars  in  this  constel- 
lation is  eighty-seven ;  of  which  six  are  of  the  2d, 
three  of  the  3d,  and  about  twice  as  many  of  the 
4th  magnitude. 

\ 
TELESCOPIC    OBJECTS. 

286  H.  I,  UHSJB  MAJORIS.— A.  R.  =  09  h.  49  m.  30  s.  Dec.  -}- 
69°  30'.  A  round  nebula,  thus  described  in  the  Bedford  Catalogue. 
'*  A  bright  class  round  nebula  at  the  back  of  Ursa  Major's  left  ear.  It  is 
lucid  white,  and  lights  up  at  the  center.  There  are  two  lines,  of  three 
stars  each,  across  the  field,  of  which  the  one  preceding  the  nebula  is  of 
the  7th  magnitude,  and  that  following  of  the  10th ;  between  these  the  sky 
is  intensely  black,  and  shows  the  nebula  as  if  floating  in  awful  and 
illimitable  space  at  an  inconceivable  distance.  Dr.  Derham,  whose 
judgment  led  him  to  consider  nebuke  as  vast  areas  of  light,  "  infallibly 
beyond  the  fixed  stars,"  thought  that  some  of  them  might  be  openings  hi 
the  opacity  surrounding  the  visible  system,  which  chasms  show  us  the 
light  of  the  empyreal  sphere  beyond  it. 

"Discovered  by  Sir  W.  Herschel  in  November  1801,  and  he  says 
that  '  on  the  north  following  side  there  is  a  faint  ray  interrupting  the 
roundness.' " 

I  have  recently  examined  this  object  with  care,  but  it  had  sunk  too  low 
to  be  well  seen.  It  appeared  fainter  than  any  of  those  whose  descriptions 
follow,  and  smaller.  It  occupies  an  insignificant  portion  of  the  field  of 
view,  arid  in  case  we  receive  it  as  a  distinct  globular  cluster,  an  "  island 
universe,"  its  distance  must  be  enormous. 

47  M.  Uttsas  MAJORIS.— A.  R.  =  11  h.  05  m.  24  s.  Dec.  =  -f- 
55°  52'  09".  Is  thus  described  in  the  Bedford  Catalogue.  "  A  large 
planetary  nebula  or  globular  collection  of  nebulous  matter,  on  the  Great 
Bear's  flank,  with  several  stars  in  the  field,  one  of  which  is  pretty  close. 
It  lies  about  2°  south-east  of  Merak,  just  south  of  the  line  joining  Merak 
and  Phad.  This  very  singular  object  is  circular  and  uniform,  and  after 


124  GEOGRAPHY  OF   THE  HEAVENS. 

a  long  inspection  looks  like  a  condensed  mass  of  attenuated  light,  seer* 
ingly  of  the  size  of  Jupiter.  Sir  W.  Herschel  remarks:  '  From  the  ob- 
servations of  the  twenty  feet  telescope,  it  appears  that  the  profundity 
of  this  object  is  beyond  the  guaging  power  of  that  instrument ;  and  as  it 
must  be  sufficiently  distant  to  be  ambiguous  it  cannot  be  less  than  that 
of  the  980th  order  ' — or  980  times  more  remote  than  Sirius." 
Discovered  by  Messier  in  1781. 

43  H.  V,  URSJE  MAJORIS.— A.  R.  =  12  h.  1 1  m.  04  s.  Dec.  =t 
-J-  48°  11'.  This  object  was  examined  by  myself  on  the  evening  of  the 
2d  July,  1 847,  when  the  following  memoranda  were  made : 

Magnifying  power  260.  The  nebula  is  elongated  north  and  south, 
stretching  nearly  across  the  field  of  view.  A  faint  star  was  seen  near 
each  extremity.  The  nebulosity  very  faint  on  the  right,  gradually  fading 
away  at  each  extremity.  The  nucleus  resembles  a  small  star  elongated 
so  as  to  cross  the  longer  axis  of  the  nebula  at  angle  of  about  30°. 

Power  500. 

The  nebula  undergoes  but  little  change.  The  nucleus  less  perfectly 
defined  than  with  the  lower  power. 

This  object  may  be  found  by  drawing  a  line  from  at  through  y  Ursa 
Majoris,  and  extending  it  about  7£°  beyond  the  last  named  star.  Al- 
though large,  it  is  faint,  and  requires  a  large  aperture  to  give  it  much 
interest.  In  case  it  be  a  universe  of  fixed  stars,  its  distance  must  be  be- 
yond the  stretch  of  imagination,  and  the  clustering  of  worlds  at  its  center 
must  be  far  greater  than  in  any  other  part  of  its  vast  extent.  It  may  be 
an  immense  annulus,  or  ring,  seen  obliquely ;  and,  possibly,  resembles 
somewhat  our  own  sidereal  stratum  in  figure. 

195  H.  I,  URSJE  MAJORIS.— A.  R.  =  11  h.  58  m.  51  s.  Dec.  == 
-f-  430  57'  03".  Described  in  the  Bedford  catalogue  as  a  bright  class 
nebula.  My  own  notes  are  in  the  following  language :  A  small,  elon- 
gated nebula,  running  nearly  north  and  south.  The  length  is  four  or 
five  times  the  breadth.  The  nucleus  is  quite  sharp.  The  entire  length 
does  not  appear  to  exceed  30"  or  40".  It  is  preceded  by  a  coarse  double 
star.  Examined  with  a  power  of  260,  and  an  aperture  of  12  inches. 

Discovered  by  Sir  William  Herschel,  1778.  Its  shape  is  not  unlike 
the  preceding  nebula,  but  its  brightness  is  much  greater.  It  requires  a 
good  instrument  to  bring  it  fairly  to  view. 

194  H.  I,  URS;E  MAJORIS.— A.  R.  =  11  h.  17m.  21  s.     Dec.  =  -j- 

44°  27'  09".  This  object  was  examined  by  myself  in  July.  1847.  It 
is  a  faint  nebula,  elongated  from  north  to  south.  There  is  a  telescopic 
star  on  the  right,  equal  in  brightness  to  the  nucleus  of  the  -nebula.  It  is 
followed  by  three  telescopic  stars,  forming  a  flat  isosceles  triangle,  whose 
vertex  points  to  the  nebula.  Its  length  is  about  50".  A  ray  from  Reg- 
ulus  to  y  Ursas  Majoris,  reaches  the  nebula  at  about  two-thirds  the  distance 
between  the  stars. 

46  H.  V,  URSJE  MAJORTS.—  R.  A.  =  1 1  h.  02  m.  02  s.  Dec.  =  -f- 
66°  31'  08".  I  find  the  nebula  elongated  in  the  direction  of  the  parallel 


CONSTELLATION  OF  URSA  MAJOR.  125 

With  a  power  of  260,  the  nebulosity  extends  half  across  the  field  of  view. 
The  nucleus  is  certainly  double.  The  smaller  point  of  light  is  below, 
and  to  the  right,  at  a  distance  of  about  10".  No  mention  is  made  of  the 
double  nucleus  by  either  Herschel,  or  by  any  astronomer  whose  descrip- 
tion has  met  my  eye. 

<T  2  URS2B  MAJOKIS.  A.  R.  =  8  h.  56  m.  13  s.  Dec.  =  -f-  67°  46' 
07".  A  double  star,  in  the  Bear's  forehead,  A  5^,  B  9£.  The  color  of 
the  principal  star  is  white,  while  its  companion  is  blue. 

Pos.  2830  00'         Dist.  7".95         Epoch  1782.42     Herschel. 
263    33  4  .59  1832.14     Striive. 

This  would  indicate  orbitual  motion ;  but,  owing  to  the  defects  in  Her- 
schel's  early  observations,  it  requires  confirmation. 

|  URSJB  MAJORIS.— A,  R.  =  11  h,  09  m.  38  s.  Dec.  =  -j-  32O  25' 
08  .  A  binary  star,  in  the  Bear's  left  hind  paw,  A  4,  B  5|,  magnitude. 

Sir  John  Herschel  finds  for  this  system  a  period  of  revolution  equal  to 
59  years.  M.  Savary  gives  58|  years  for  its  period.  In  case  these  re- 
sults are  reliable,  a  knowledge  of  the  distance  of  this  system  would  give 
to  us  the  relative  magnitude  of  the  stars,  and  their  mass,  compared  with 
our  sun. 

Pos.   143047'         Dist.  3".50         Epoch  1780.33     Herschel. 
229    30  1  .82  1827.26     Striive. 

143    20  2  .30  1843.16     Smyth. 

Here  is  exhibited  a  complete  revolution  of  the  angle  of  position  through 
360°,  from  the  epoch  of  the  first  observation  to  that  of  the  last. 

v  URSJE  MAJORIS— A.  R.  =  11  h.  09  m.  49  s.     Dec.  =  -f  33O  ?>&. 
A  double  star,  on  the  Bear's  left  hind  foot,  A  4,  B  12. 
Pos.   147°  02'         Dist.  7".8         Epoch  1834.31 

£  URsas  MAJORTS  MIJAR. — A.  R.  =  13  h.  17  m.  28  s.     Dec.  =  -|- 

550  4.V  08".  A  beautiful  double  star,  in  the  middle  of  the  tail  of  the 
Bear,  A  3,  B  5,  magnitude. 

Pos.    1450  20'         Dist.  14".24         Epoch  1819.70     Struve. 
147    24  14  .40  1839.32     Smyth. 

It  is  uncertain  whether  any  physical  connection  exists  between  the  two 
components,  though  an  identity  of  proper  motion  would  lead  us  to  think 
them  united.  In  exhibiting  this  double  star  to  those  not  familiar  with 
the  heavens,  on  taking  the  eye  from  the  telescope,  and  looking  at  the 
star  with  the  unaided  vision,  many  persons  exclaim  that  they  see  the 
small  star  with  the  naked  eye.  This  is,  however,  a  mistake.  The  faint 
star  really  seen  is  not  the  one  shown  by  the  telescope,  but  a  much  more 
distant  minute  star,  called  Alcor.  Indeed,  with  the  great  refractor  of  the 
Cincinnati  Observatory,  Alcor,  which  to  the  eye  appears  so  very  close  to 
Mizar,  does  not  even  fall  within  that  field  of  view  of  the  telescope,  which 
is  occupied  by  Mizar  in  its  center. 

From  the  fact  that  Alcor  and  Mizar  have  an  identity  of  proper  motion, 
it  has  been  argued  that  they  may  constitute  a  binary  system — two  suns 
revolving  around  their  common  center  of  gravity.     Should  this  be  true, 
L2 


126  GEOGRAPHY   OF  THE  HEAVENS. 

and  their  distance  be  assumed  as  great  as  that  assigned  to  stars  of  the 
same  magnitude,  they  cannot  complete  their  revolution  in  a  period  less 
than  190,000  of  our  years! 

In  the  Memoirs  of  the  Observatory  of  the  Collegio  Romano,  1842, 
some  singular  notices  of  Mizar  are  made,  which  I  venture  to  translate. 

I  give  the  substance  of  the  notices  as  follows  : 

On  the  18th  April,  1841,  M.  Mlidler  communicated  to  M.  Arago  the 
singular  fact  that,  at  9  o]clock  and  8  minutes,  on  that  evening,  he  had 
seen  Mizar  without  a  companion.  About  10  o'clock,  the  small  star  re- 
appeared in  all  its  brilliancy.  He  thinks  he  had  observed  the  same 
phenomenon,  with  an"  inferior  instrument,  in  1 834,  and  infers  that  the 
small  star  is  variable,  with  a  long  period.  The  Italian  astronomers  report 
the  detection  of  four  minute  points  in  the  same  field  with  Mizar,  some  or 
all  of  which  appear  to  be  variable. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XIII. 

BOOTES — THE  BEAR  DRIVER. 
CORONA  BOREALIS — THE  NORTHERN  CROWN. 
.  QUADRANS — THE  QUADRANT. 
CANES  VENATICI — THE  GREY  HOUNDS. 
COMA  BERENICES — BERENICES'   HAIR. 
Favorably  situated  for   examination   in  May,  June 
and  July. 

P  0  O  T  E  S  . 

THE  BEAR  DRIVER  is  represented  by  the  figure  of  a 
huntsman  in  a  running  posture,  grasping  a  club  in 
his  right  hand,  and  holding  up  in  his  left  the  leash 
of  his  two  grey  hounds,  Asterion  and  Chara,  with 
which  he  seems  to  be  pursuing  the  Great  Bear  round 
the  pole  of  the  heavens.  He  is  thence  called  Arcto- 
phylax,  or  the  "  Bear  Driver." 

This  constellation  is  situated  between  Corona 
Borealis,  on  the  east,  and  Cor  Caroli,  or  the  Grey- 
hounds, on  the  west.  It  contains  fifty-four  stars 


-       CONSTELLATION  OF  BOOTES.  127 

including  one  of  the  1st  magnitude,  seven  of  the  3d, 
and  ten  of  the  4th.  Its  mean  declination  is  20° 
•N.,  and  mean  right  ascension  is  212° ;  its  center  is 
therefore  on  the  meridian  the  9th  of  June. 

Bootes  may  be  easily  distinguished  by  the  position 
and  splendor  of  its  principal  star,  Arcturus,  which 
shines  with  a  reddish  luster,  very  much  resembling 
that  of  the  planet  Mars. 

Arcturus,  marked  a,  is  a  star  of  the  1st  magnitude, 
situated  near  the  left  knee,  26°  S.  E.  of  Cor  Caroli 
and  Coma  Berenices,  with  which  it  forms  an  elon- 
gated triangle,  whose  vertex  is  at  Arcturus. 

Five  or  six  degrees  S.  W.  of  Arcturus  are  three  stars  of  the  3d  and 
4th  magnitudes,  lying  in  a  curved  line,  about  2°  apart,  and  a  little  below 
the  left  knee  of  Bootes;  and  about  7°  E.  of  Arcturus  are  three  or  four 
other  stars  of  similar  magnitude,  situated  in  the  other  leg,  making  a 
larger  curve  N.  and  S. 

Mirac,  marked  e,  in  the  girdle,  is  a  star  of  the  3d  magnitude,  10°  N. 
N.  E.  of  Arcturus,  and  about  11°  W.  of  Alphacca,  or  <*  in  the  Northern 
Crown.  Seginus,  marked  -y,  in  the  west  shoulder,  is  a  star  of  the  3d 
magnitude,  nearly  20°  E.  of  Cor  Caroli,  and  about  the  same  distance  N. 
of  Arcturus,  and  forms,  with  these  two,  a  right  angled  triangle,  the  right 
angle  being  at  Seginus. 

Alkaturops,  marked  p,  situated  in  the  top  of  the  club,  is  a  star  of  the 
4th  magnitude,  about  10  3°  in  an  easterly  direction  from  y,  which 
lies  in  the  left  shoulder :  and  about  4£°  S.  of  Alkaturops  is  another  star 
of  the  4th  magnitude,  in  the  club  near  the  east  shoulder,  marked  Delta 
tT  is  about  9°  distant  from  Mirac,  and  73°  from  Alphacca,  and  forms,  with 
these  two,  a  regular  triangle. 

Nekkar,  marked  /2,  is  a  star  of  the  3d  magnitude,  situated  in  the  head, 
and  is  about  6°  N.  E.  of  Seginus,  and  5°  W.  of  Alkaturops  ;  it  forms 
with  tT  and  Seginus,  nearly  a  right  angled  triangle,  the  right  angle  being 
at  Nekkar, 

These  are  the  principal  stars  in  this  constellation,  except  the  three  stars 
of  the  4th  magnitude  situated  in  the  right  hand.  These  stars  may  be 
known,  by  two  of  them  being  close  together,  and  about  5°  beyond 
Benetnasch,  the  first  star  in  the  handle  of  the  Dipper.  About  6°  B.  of 
Benetnasch  is  another  star  of  the  4th  magnitude,  situated  in  the  arm, 
which  forms,  with  Benetnasch  and  the  three  in  the  hand,  an  equilateral 
triangle. 

Arcturus  is  mentioned  by  name  in  that  beautiful 
passage  in  Job,  already  referred  to,  where  the 


128  GEOGRAPHY   OF   THE  HEAVENS. 

Almighty  answers    "  out  of  the   whirlwind,"  and 
says  : 

"  Canst  them  the  sky's  benevolence  restrain, 
A  nd  cause  the  Pleiades  to  shine  in  vain  1 
Or,  when  Orion  sparkles  from  his  sphere, 
Thaw  the  cold  seasons  and  unbind  the  year  ? 
Bid  Mazzaroth  his  station  know, 
And  teach  the  bright  Ardurus  where  to  glow  !  " 

Young's  Paraphrase. 

TELESCOPIC    OBJECTS. 

i  Bor.Tis.— A.  R.  =  14  h.  10  m.  30  s.  Dec.  =  -f-  52°  06'  04".  A 
delicate  triple  star  in  the  right  hand  of  Bootes.  A  4£,  B  4£,  C  8, 
magnitude. 

Discovered  by  Struve. 

A  B  Pos.  149°  00'         Dist.  00". 3  Epoch  1836.28  ?  ~    ., 

AC  33    09  38  .06  1836.28  5  Ot 

A  WHITE  ROUND  NEBULA.— 14  h.  11  m.  44  s.    Dec.  =  37°  14'  04" 
Discovered  by  Herschel,  on  1st  May,  1785. 

A  NKAT  DOUBLE  STAR. — A.  R.  =  14  h.  15  m.  31  s.  Dec.  =  -f- 
09°  10'  07".  Between  the  left  foot  of  Bootes  and  Virgo,  on  a  line  be- 
tween Spica,  £  Bootis.  A  6,  B  white,  B  7£,  blue. 

Discovered  by  Piazzi. 

Pos.  186003'         Dist.  06".26         Epoch  1825.40     Struve. 

TT  BOOTIS.— A.  R.  =  14  h.  33  m.  12  s.  Dec.  =  -f-  l?o  06'  05". 
On  the  left  leg.  A  3£,  B  6,  magnitude.  ' 

Pos.  99003'         Dist.  08".00         Epoch  1836.51     Smyth. 

96    57  08  .28  1847.60     Mitchel. 

f  BOOTIS.— A.  R.  =  14  h.  33  m.  31  s.  Dec.  =  -f-  140  25'  01". 
A  close  double  star  on  the  left  leg  of  Bootes.  A  3£,  B  4£. 

Discovered  by  Herschel,  1796. 

Pos.  1290  IT         Dist.  05".  190         Epoch  1830.47     Struve. 
128    24  06  .924  1847.62     Mitchel. 

This  result,  after  an  interval  of  seventeen  years,  determines,  it  would 
seem,  the  fixity  of  the  components,  though  from  early  observations  mo- 
tion had  been  suspected. 

«  BOOTIS.— A.  R.  =  14  h.  38  m.  00  s.  Dec.  ==  -f-  27°  45'  01".  A 
fine  double  star  on  the  left  hip  of  Bo  tes.  A  3,  pale  orange;  B  7,  sea 
green.  This  is  certainly  one  of  the  most  beautLoil  among  the  double 
stars. 

Discovered  by  Herschel. 

Pos.  320°  47'         Dist.  02".  581         Epoch  1831.41     Struve. 
323    38  02  .917  1841.41     Mlldler. 

320    50  02  .568  1846.66     Mitchel. 


CONSTELLATION   OF   BOOTES.  129 

£  BoC-ris.— A.  R.  =  14  h.  44  m.  00  s.  Dec.  =  -f-  19°  46'  01".  A 
binary  star  on  the  left  knee  of  Bootes.  A  3£,  orange ;  B  6^,  purple. 
The  orbit  was  computed  by  Sir  John  Herschel  in  18:33,  but  with  little 
success.  Mildler  thinks  the  periodic  time  cannot  be  nearly  so  short  as 
that  obtained  by  Herschel.  It  will  probably  exceed  400  years. 
Discovered  by  Herschel,  1780. 

Pos.  334°  10'         Dist.  07".22         Epoch  1829.46     Stn.ve. 
324    41  07  .09  1841.43     M:;dler. 

317    44  06  .482  1817.63     Mitchel. 

A  SMALL  NEBULA.— A.  R.  =  14  h.  53  m.  53  s.     Dec.  =  -j-  54° 
32'  07".     Between  the  right  hand  of  Bootes  and  Draco. 
Discovered  by  Herschel,  1788. 

39  BOOTIS.— A.  R.  =  14  h.  44  m.  16  s.  Dec.  =  -f-  49°  22'  08". 
On  the  right  wrist  of  Bootes.  A  5£,  B  6£,  magnitude. 

Pos.  440  12'         Dist  03".  71          Epoch   1830.02     Struve. 
37    00  04  .00  1847.60     Mitchel. 

These  measures  show  a  retrograde  motion,  as  do  all  the  previous  ones.* 

44  Boons.— A.  R.  =  14  h.  58  m.  31  s.  Dec.  =  -f-  48°  16'  08". 
A  close  double  star  in  the  space  following  the  right  arm  of  Bo"tes.  A 
5,  B  6,  magnitude.  This  star  has  occasioned  no  little  difficulty,  owing 
to  the  abrupt  changes  which  have  occurred  in  the  relative  positions  of  the 
components.  Mildler  thinks  Herschel's  first  observation  is  wrong  by  180 
degrees  ;  an  error  easily  committed,  considering  the  near  equality  of  the 
two  stars.  On  this  hypothesis  the  periodic  time  may  not  differ  much 
from  sixty  or  seventy  years.  A  few  measures  are  added. 

Pos.    60006'         Dist.  02".00         Epoch  1781.62     Herschel. 

228    00  01  .50  1819.43     Struive. 

233    39  02  .55  1829.30     Struve. 

237  02  04  .068  1841.47     Midler. 

238  20  03  .738  1847.62     Mitchel. 

p  2  BOUTIS.— A.  R.  =  15  h.  18  m.  28  s.     Dec.  =  -j-  -37°  54'  07". 
A  binary  star  on  the  tip  of  the  staff  of  Bootes.     A  8,  B  8£,  magnitude. 
The  components  are  preforming  their  revolution  in  a  retrograde  order, 
and  in  a  period  of  300  or  400  years. 

1'hese  measures  will  show  the  rate  of  motion. 
Pos.  3570  14'         Dist.  Epoch  1782.68     Herschel. 

327    00  01  ".385  1826.77     Struve. 

315    04  01   .060  1830.65     Struve. 

308    43  06  .885  1841.46     Madler. 


130  GEOGRAPHY  OF  THE  HEAVENS. 


DRACO.* 

THE  DRAGON. — This  constellation,  which  com- 
passes a  large  circuit  in  the  polar  regions  by  its 
ample  folds  and  contortions,  contains  many  stars 
which  may  be  easily  traced. 

From  the  head  of  the  monster,  which  is  under  the 
foot  of  Hercules,  there  is  a  complete  coil  tending 
eastwardly,  about  17°  N.  of  Lyra ;  thence  he  winds 
down  northerly  about  14°  to  the  second  coil,  where 
he  reaches  almost  to  the  girdle  of  Cepheus,  then  he 
loops  down  somewhat  in  the  shape  of  the  letter  U, 
and  makes  a  third  coil  about  15°  below  the  first. 
From  the  third  coil  he  holds  a  westerly  course  for 
about  13°,  then  goes  directly  down,  passing  be- 
tween the  head  of  the  Lesser  and  the  tail  of  the 
Greater  Bear. 

This  constellation  contains  eighty  stars,  including 
four  of  the  2d  magnitude,  seven  of  the  3d,  and  twelve 
of  the  4th. 

*...  "  The  Dratrwi  next,  winds  like  a  mighty  stream ; 

Within  its  ample  folds  are  eighty  stars, 
Four  of  the  second  order.     Far  he  waves 
His  ample  spires,  involving  either  Bear." 

The  head  of  the  Dragon  is  readily  distinguished 
by  means  of  four  stars,  3°,  4°,  and  5°  apart,  so  situ- 
ated as  to  form  an  irregular  square  ;  the  two  upper 
ones  being  the  brightest,  and  both  of  the  2d  magni- 
tude. The  right  hand  upper  one,  called  Etanin,  has 
been  rendered  very  noted  in  modern  astronomy  from 
its  connection  with  the  discovery  of  a  new  law  in ' 
physical  science,  called  the  Aberration  of  Light. 

The  letter  name  of  this  star  is  Gamma,  or  Gamma 
Draconis ;  and  by  this  appellation  it  is  most  fre- 
quently called.  The  other  bright  star,  about  4° 
from  it  on  the  left,  is  Rastaben,  marked  £. 

*  See  Map  XVII  for  part  of  Draco. 


CONSTELLATION   OF  DRACO.  131 

About  4°  W.  of  ]3,  a  small  star  may,  with  close 
attention,  be  discerned  in  the  nose  of  the  Dragon, 
which,  with  the  irregular  square  before  mentioned, 
makes  a  figure  somewhat  resembling  an  Italic  F, 
with  the  point  towards  the  west,  and  the  open  part 
towards  the  east.  The  small  star  in  the  nose,  is 
called  Er  Rakis,  marked  p. 

The  two  small  stars  5°  or  6°  S.  of  Rastaben  are  in  the  left  foot  of 
Hercules. 

Rastaben  is  on  the  meridian  nearly  at  the  same 
moment  with  Ras  Alhague.  Etanin,  40°  N.  of  it,  is 
on  the  meridian  about  the  4th  of  August,  at  the 
same  time  with  the  three  western  stars  in  the  face 
of  Taurus  Poniatowski,  or  the  V.  It  is  situated 
less  than  2°  west  of  the  solstitial  colure,  and  is 
exactly  in  the  zenith  of  London.  Its  favorable 
position  has  led  English  astronomers  to  watch  its 
appearance,  for  long  periods,  with  the  most  exact 
and  unwearied  scrutiny. 

In  the  year  1725,  Mr.  Molyneux  and  Dr.  Bradley  fitted  up  a  very 
accurate  and  costly  instrument,  in  order  to  discover  whether  the  fixed 
stars  had  any  sensible  parallax,  while  the  earth  moved  from  one  extremity 
of  its  orbit  to  the  other ;  or  which  is  the  same,  to  determine  whether  the 
nearest  fixed  stars  are  situated  at  such  an  immense  distance  from  the 
earth,  that  any  star  which  is  seen  this  night  directly  north  of  us,  will,  six 
months  hence,  when  we  shall  have  gone  1 90  millions  of  miles  to  the 
eastward  of  the  place  we  are  now  in,  be  then  seen  exactly  north  of  us 
still,  without  changing  its  position  so  much  as  the  thickness  of  a 
spider's  web. 

These  observations  were  subsequently  repeated,  with  but  little  inter- 
mission, for  twenty  years,  by  the  most  acute  observers  in  Europe,  and 
with  telescopes  varying  from  twelve  to  thirty-six  feet  in  length.  In  the 
meantime,  Dr.  Bradley  had  the  honor  of  announcing  to  the  world  the  very 
nice  discovery,  that  the  motion  of  light,  combined  with  the  progressive 
motion  of  the  earth  in  its  orbit,  causes  the  heavenly  bodies  to  be  seen  in 
a  different  position  from  what  they  would  be,  if  the  eye  were  at  rest. 
Thus  was  established  the  principle  of  the  Aberration  of  Light. 

This  principle,  or  law,  now  that  it  is  ascertained,  seems  not  only  very 
plain,  but  self  evident.  For  if  light  be  progressive,  the  position  of  the 
telescope,  in  order  to  receive  the  ray,  must  be  different  from  what  it  would 
have  been,  if  light  had  been  instantaneous,  or  if  the  earth  stood  still. 


132  GEOGRAPHY   OF  THE   HEAVENS. 

Hence  the  place  to  which  the  telescope  is  directed,  will  be  different  from 
Jie  true  place  of  the  object. 

The  quantity  of  this  aberration  is  determined  by  a  simple  proj>osition. 
The  earth  describes  59'  8"  of  her  orbit  in  a  day  =  3548",  and  a  ray  of 
light  comes  from  the  sun  to  us  in  8'  13"  =  493"  :  now  twenty -four  hours 
or  86400"  :  493"  : :  3548"  :  22" ;  which  is  the  change  in  the  star's  place, 
arising  from  the  cause  above  mentioned. 

Of  the  four  stars  forming  the  irregular  square  in  the  head,  the  lower 
and  right  hand  one  is  5^°  N.  of  Etanin.  It  is  called  Grumium,  and  is 
of  the  4th  magnitude.  A  few  degrees  E.  of  the  square,  may  be  seen, 
with  a  little  care,  eight  stars  of  the  5th  magnitude,  and  one  of  the  4th, 
which  lies  8°  E.  of  Grumium.  This  group  is  in  the  first  coil  of  the 
Dragon. 

The  second  coil  is  about  13°  below  the  first,  and  may  be  recognised 
by  means  of  four  stars  of  the  3d  and  4th  magnitudes,  so  situated  as  to 
form  a  small  square,  about  half  the  size  of  that  in  the  head. 

The  brightest  of  them  is  on  the  left,  and  is  marked  Delta.  A  line 
drawn  from  Rastaben  through  Grumium,  and  produced  about  14°,  will 
point  it  out.  A  line  drawn  from  Lyra  through  Zi  Draconis,  and  pro- 
duced 10°  farther,  will  point  out  Zeta,  a  star  of  the  :*d  magnitude,  situated 
in  the  third  coil.  £"  may  otherwise  be  known,  by  its  being  nearly  in  a 
line  with,  and  midway  between.  Etanin  and  Koohab.  From  £  the  re- 
maining stars  in.  this  constellation  are  easily  traced. 

Eta,  7'heta,  and  Arich,  come  next ;  all  stars  of  the  3d  magnitude,  and 
at  the  distance,  severally,  of  6°,  40  anc|  50  frOm  £  At  Asich,  the  third 
star  from  £  the  tail  of  the  Dragon  makes  a  sudden  crook.  Thubun, 
Kappa,  Giansar,  follow  next,  and  complete  the  tail. 

Thuban,  marked  a,  is  a  bright  star  of  the  3d  mag- 
nitude, 11°  from  Asich,  in  a  line  with,  and  about 
midway  between,  Mizar  and  the  southernmost  guard 
in  the  Little  Bear.  By  nautical  men  this  star  is 
called  the  Dragon's  Tail,  and  is  considered  of  much 
importance  at  sea.  It  is  otherwise  celebrated  as 
being  formerly  the  north  polar  star.  About  2,300 
years  before  the  Christian  era,  Thuban  was  ten 
times  nearer  the  true  pole  of  the  heavens  than 
Cynosura  now  is. 

Kappa  is  a  star  of  the  3d  magnitude,  10°  from  Alpha,  between  Megrez 
and  the  pole.  Mizar  and  Megrez,  in  the  tail  of  the  Great  Bear,  form, 
with  Thuban  and  x.,  in  the  tail  of  the  Dragon,  a  large  quadrilateral  figure, 
whose  longest  side  is  from  Megrez  to  *. 

Giansar,  the  last  star  in  the  tail,  is  between  the  3d  and  4th  magni- 
tudes, and  5°  from  K.  The  two  pointers  will  also  point  out  Giansar, 
lying  at  the  distance  of  little  more  than  8°  from  them,  and  in  the  direction 
of  the  pole. 


CONSTELLATION   OF  DRACO.  133 

TELESCOPIC     OBJECTS. 

AN  OVAL  NEBULA.— A.  R.  =  15  h.  02  m.  03  s.  Dec.  =  -\-  56° 
23'.  Under  the  body  of  Draco. 

Discovered  by  Herschel,  1789.     It  is  faint  at  the  edges. 

A  SMALL  ROUND  NEBULA. — A.  R.  =  15 h.  35  m.  53  s.  Dec.  -|- 
59°  52'.  In  the  center  of  Draco's  body. 

Discovered  by  Herschel,  1788. 

This  object  brightens  at  the  center,  presenting  a  nucleus  not  very  per- 
fectly denned.  It  is  followed  in  the  same  field  by  a  much  larger  elon- 
gated nebula,  which  seems  to  have  escaped  all  preceding  observers.  It 
was  discovered,  4th  July,  1847,  by  Mrs.  Mitchel,  while  engaged  in  a 
critical  examination  of  the  abova  object.  It  is  faint,  but  certain,  and  haa 
an  oval  or  elliptical  figure. 

p.  DRACONIS A.  R.  =  17  h.  02  m.  02  s,    Dec.  =  54°  41'  02".     A 

fine  binary  star,  on  the  tip  of  Draco's  tongue.     A  4,  B  4^,  magnitude. 
Discovered  by  Herschel,  1781.     Since  which  period  a  retrograde  mo- 
tion has  been  in  progress,  as  is  fully  sustained  by  the  reported  measures, 
viz. — 

Pos.  2320  22'         Dist.  4".35         Epoch  1781.73     Herschel. 
205    06  3  .23  1832.22     Stn.ve. 

190    57  2  .90  1847.70     Mitchel. 

4  1  DHACOXIS.— A.  R.  =  17  h.  44  m.  47  s.  Dec.  -f-  71°  I.T.  A 
double  star,  in  the  middle  of  Draco's  back.  A  5£,  B  6.  Both  white. 
This  distance  is  about  3 1 ";  the  position  15°.  No  change  seems  to 
have  taken  place.  See  Map,  No  XVII. 

A  DOUBLE  STAR.— A.  R.  =  17  h.  25  m.  07  s.  Dec.  =  -\-  50°  59' 
09".  Between  the  right  foot  of  Hercules  and  Draco's  eye.  A  8,  B  8£, 
magnitude. 

Pos.  265°  28'         Dist.  3".  17         Epoch  1831.29     Strive. 
266    20  3  .03  1847.70     Mitchel. 

A  PLANETARY  NEBULA.— A.  R.  ^=  17  h.  58  m.  39  s.  Dec.  66O  38'. 
Between  the  first  twist  of  Draco  and  his  head. 

Discovered  by  Herschel,  in  1786. 

This  singular  object  is  described  in  the  Bedford  Catalogue,  without 
any  mention  of  a  remarkably  bright  but  .small  nucleus  which  occupies  its 
center.  This  point  was  detected  by  myself,  July,  1847.  When  the 
eye  and  attention  is  attentively  fixed  on  the  central  point,  the  nebula 
fades  from  the  view,  and  the  moment  the  attention  is  withdrawn  from 
the  nucleus,  and  a  casual  glance  is  directed  to  the  nebula,  the  star  fades 
and  the  nebula  brightens  up  in  a  most  beautiful  manner.  This  curious 
phenomenon  was  noticed  by  many  persons  in  my  company.  No  one 
can  doubt  the  connection  between  this  nebulous  mass  and  the  round 
central  point  of  light.  It  is  unlike  a  star,  as  it  is  round  and  clear,  with  a 
minute  disk  and  no  radiations.  I  have  discovered  but  one  other  object 
like  it.  Here  is  the  connecting  link  between  planetary  nebulse  and 
JVL 


134  GEOGRAPHY  OF  THE  HEAVENS. 

nebulous  stars ;   at  least,  such  would  be  the  opinion  of  those  who  still 
adhere  to  the  nebulous  theory. 

This  remarkable  object,  as  will  be  seen  from  the  position,  is  in  the  pole 
of  the  ecliptic. 

o  DHACONIS.— A.  R.  =  18  h.  48  m.  50  s.     Dec.  =  -}-  59°  11'  07". 
A  double  star,  on  Draco's  neck.     A  5,  B  9,  magnitude.     Midler  thinks 
the  components  physically  connected,  with  a  period  of  about  1600  years. 
Pos.     OOOQO'          Dist  26". 37         Epoch  1781.68     Herschel. 
346    33  30  .26  1832.50     Strilve. 

344    51  32  .10  1841.48     Mildler. 

t  DRACOJTIS.— A.  R  =  19  h.  48  m.  41  s.  Dec.  69°  51'  06".  In  the 
bend  of  Draco's  back.  A  5£,  B  9^,  magnitude. 

Discovered  by  Herschel,  whose  first  measures  are  probably  wrong  in 
some  way,  as  they  would  indicate  a  great  motion,  between  1781  and 
1804,  which  is  not  sustained  by  the  later  observations. 

Pos.   355040'         Dist.  2".6 9:3         Epoch   184]. 55     Mlldler. 


COMA    BERENICES. 

BERENICE'S  HAIR. — This  is  a  beautiful  cluster  of 
small  stars,  situated  about  5°  E.  of  the  equinoctial 
colure,  and  midway  between  CorCaroli  on  the  north- 
east, and  Denebola  on  the  southwest.  If  a  straight 
line  be  drawn  from  Benetnasch  through  Cor  Caroli, 
and  produced  to  Denebola,  it  will  pass  through  it. 

The  principal  stars  are  of  between  the  4th  and  5th 
magnitudes.  According  to  Flamsted,  there  are  thir- 
teen of  the  4th  magnitude,  and,  according  to  others, 
there  are  seven ;  but  the  student  will  find,  agreeably 
to  his  map,  that  there  are  but  three  stars  in  this 
group  entitled  to  that  rank. 

Although  it  is  not  easy  to  mistake  thjs  group  for 
any  other  in  the  same  region  of  the  skies,  yet  the 
stars  which  compose  it  are  all  so  small  as  to  be 
rarely  distinguished  in  the  full  presence  of  the 
moon.  The  confused  luster  of  this  assemblage  of 
small  stars,  somewhat  resembles  that  of  the  Milky- 
Way.  It  contains,  besides  the  stars  already  alluded 
to,  a  number  of  nebulae. 


CONSTELLATION  OF  COMA  BERENICES.  135 

The  whole  number  of  stars  in  this  constellation 
is  43;  its  mean  right  ascension  is  185°.  It,  conse- 
quently, is  on  the  meridian  the  13th  of  May. 


Now  behold 


The  glittering  maze  of  Berenices  Hair  ; 
Forty  the  stars  ;   but  such  as  seem  to  kiss 
The  flowing  tresses  with  a  lambent  fire : 
Four  to  the  telescope  alone  are  seen." 

TELESCOPIC     OBJECTS. 

35  COMJE  BERNICES.— A.  R.  =  12  h.  45  m.  25s.  Dec.  =4.  22° 
07'.  A  triple  star,  between  the  Tresses  and  Virgo's1  northern  wing. 
A  5,  B  indistinct,  C  10.  Such  are  the  magnitudes  assigned  by  Captain 
Smyth.  I  measured  the  components  on  the  *27th  July,  1847,  and  found 
the  individual  measures  accord  well  with  each  other. 

Pos.  A  B  =  400  04'         Dist.  =  I".3l6         Epoch  as  above. 
AtoC  125    31 

In  1 830,  Strilve  gives  the  measures  of  A  to  C  as  follows : 

Pos.  AtoC   124043'         Dist.   28".61         Epoch  1830.13. 

Captain  Smyth  makes  the  distance  between  A  and  B,  in  1834,  T'.OO. 
In  1843,  1".5. 

64  MESSIER,  Coyim  BERNICES.— A.  R.  =  12  h.  48  m.  52  s.  Dec. 
-f-  22°  33'  02".  A  large  elliptical  nebula,  between  Bernice's  hair  and 
Virgo's  left  arm. 

Discovered  by  Messier,  1780. 

Sir  John  Herschel  considers  this  nebula  resolvable,  though  not  re- 
solved. He  says :  "  I  am  much  mistaken  if  the  nucleus  be  not  a  double 
star,  in  the  general  direction  of  the  nucleus ;  320  much  increases  this  sus- 
picion ;  340  shows  well  a  vacuity  below  the  nucleus." 

53  MESSIER,  COM*:  BERNICES. — A.  R.  =  13  h.  05  m.  03  s.  Dec. 
=  -|-  19°  01'  03".  A  globular  cluster,  between  the  Coma  and  Virgo's 
left  hand.  A  brilliant  mass  of  minute  stars,  varying  from  the  llth  to 
the  16th  magnitudes. 

Discovered  by  Messier,  1774.  Resolved  by  Herschel,  who  finds  it 
greatly  compressed  at  the  center.  This  is  one  of  the  many  magnificent 
"  island  universes." 

Sir  John  Herschel,  with  his  20  feet  reflector,  saw  this  object  with 
curved  radiations  of  stars,  somewhat  resembling  the  claws  of  a  crab. 

42  COM;E  BERNICES.— A.  R.  ==  13  h.  02  m.  12  s.     Dec.  =  -f-  18° 

22'  06".     A  very  close  double  star,  between  the  Lady's  hair  and  Virgo's 
left  hand.     A  4^,  B  5,  magnitude.     Both  stars  are  said  to  be  pale-yel- 
low.    It  is  No.  1728  of  StriJve's  great  catalogue,  and  is  among  his 
"  vicinissimae,"  or  very  closest  stars. 
The  measures  run  thus : 


136  GEOGRAPHY   OF   THE   HEAVENS. 

Pos.    09°30'       Dist.  Epoch  1827.83     Strive. 

11    06  0".649  1829.40 

—    —  single  1833.37 

228     18  somewhat  elongated  1834.43 

191     12  1335.39 

After  this,  the  measures  are  made  with  Jittle  variation,  up  to  18-11. 
when  Madler,  of  Dorpat,  gives  these  : 

Pos.   183°  15'         Dist  0".327         Epoch   1841.45. 
Here  is,  doubtless,  a  binary  system,  but  one  of  great  difficulty.     The 
stars  being  nearly  equal  in  magnitude,  it  is  difficult  to  distinguish  the 
angle  of  position  from  the  same,  increased  by  180°. 


ASTERION  ET  CHARA;   VEL  CANES  VENATICI. 

THE  GREYHOUNDS.  —  This  modern  constellation, 
embracing  two  in  one,  was  made  by  Hevelius  out 
of  the  unformed  stars  of  the  ancients,  which  were 
scattered  between  Bootes  on  the  east,  and  Ursa 
Major  on  the  west,  and  between  the  handle  of  the 
Dipper  on  the  north,  and  Coma  Berenices  on  the 
south. 

These  Hounds  are  represented  on  the  celestial 
sphere  as  being  in  pursuit  of  the  Great  Bear,  which 
Bootes  is  hunting  round  the  pole  of  heaven,  while 
he  holds  in  his  hand  the  leash  by  which  they  are 
fastened  together.  The  northern  one  is  called  As- 
tcrion,  and  the  southern  one  Chara. 

The  stars  in  this  group  are  considerably  scatter- 
ed, and  are  principally  of  the  5th  and  6th  magni- 
tudes ;  of  the  twenty-five  stars  which  it  contains, 
there  is  but  one  sufficiently  large  to  engage  our  at- 
tention. Cor  Caroli,  marked  a,  or  Charles's  Heart, 
so  named  by  Sir  Charles  Scarborough,  in  memory 
of  King  Charles  the  First,  is  a  star  of  the  3d  mag- 
nitude, in  the  neck  of  Chara,  the  southern  Hound. 

When  on  the  meridian,  Cor  Caroli  is  17^°  directly  south  of  Alioth, 
the  third  star  in  the  handle  of  the  Dipper,  and  is  so  nearly  on'  the  same 
meridian,  that  it  culminates  only  one  minute  and  a  half  after  it.  This 
occurs  on  the  20th  of  May. 

A  line  drawn  from  Cor  Caroli,  through  Alioth,  will  lead  to  the  north 
polar  star.  This  star  may  also  be  readily  distinguished  by  its  being  in  a 


CONSTELLATION  OF   THE   HOUNDS.  137 

straight  line  with,  and  midway  between,  JBenetnasch,  the  first  star  in  the 
handle  of  the  Dipper,  and  Coma  Berenices :  and,  also,  by  the  fact  that, 
when  Cor  Caroli  is  on  the  meridian,  Denehola  bears  28°  S.  W.,  and 
Arcturus  26°  S.  E.  of  it,  forming,  with  these  two  stars,  a  very  large  tri- 
angle, whose  vertex  is  at  the  north.  It  is  also  at  the  northern  extremity 
of  the  large  Diamond,  already  described. 

The  remaining  stars  in  this  constellation  are  too  small,  and  too  much 
scattered,  to  excite  our  interest. 

•   . 
'  ?  « 
TELESCOPIC    OBJECTS. 

2  CAWVM   VEJTATICORUM.— A.  R.  =  12  h.  08  m.  06  s.     Dec.  =  -f- 
410  33'.     A  double  star,  near  Chara's  mouth.     A  6,  yellow ;  B  9,  blue. 

Discovered  by  Herschel,  1782. 

Pos.  2590  38'         Dist  11  ".42         Epoch  1832.16     Struve.     . 
Its  fixity  seems  to  be  determined  by  a  comparison  of  all  the  recorded 
observations. 

A  LARGE  NEBULA. — A.  R.  =  12  h.  43  m.  2  '  s.  Dec.  41°  5*9'  07". 
Immediately  preceding  the  Crown,  or  Charles's  Heart. 

Discovered  by  Michain,  in  1781.  Described  in  the  Bedford  Catalogue 
as  "  a  fine  pale  white  object,  with  evident  symptoms  of  being  a  com- 
pressed cluster  of  small  stars." 

51  M.  CAHTUM  VENATICORUM. — A.  R.  =  13  h.  23m.  06s.  Dec. 
=  -f-  48°  01'  07".  A  pair  of  lucid  nebula,  near  the  ear  of  Asterion. 

Discovered  by  Messier,  1772.  Figured  by  Sir  John  Herschel,  1830. 
Resolved  by  Lord  Rosse,  into  one  magnificent  cluster,  in  the  shape  of  an 
immense  whirlpool,  in  1847. 

I  have  repeatedly  examined  this  most  wonderful  object  with  the  12 
inch  refractor  of  the  Cincinnati  Observatory.  The  large  nebula  is  seen 
with  a  bright  nucleus,  surrounded  by  a  ring  of  hazy  light,  which  is  di- 
vided, in  a  part  of  its  circumference,  into  two  branches,  which '  forcibly 
remind  me  of  the  Milky- Way  and  its  division.  The  smaller  nebula  is 
round,  and  its  light  is  seen,  nearly,  if  not  quite,  commingling  with  that  of 
the  ring  surrounding  the  principal  object.  This  object  strongly  resembled 
our  own  great  stellar  system,  so  long  as  it  was  viewed  at  the  distance 
to  which  ordinary  telescopes  could  carry  the  beholder.  But,  under  the 
gaze  of  Lord  Rosse's  stupendous  reflector,  the  most  bewildering  object 
bursts  upon  the  sight.  A  mighty  center,  where,  in  spiral  curves,  radiate 
masses  of  light,  so  vast  as  to  overwhelm  the  imagination. 

The  resolution  of  this  most  remarkable  nebula  is  one  of  the  great 
achievements  of  Lord  Rosse's  telescope. 

3  MESSIER,  CAJTUM  VEXATTCORUM. — A.  R.  =  13  h.  34  m.  45  s. 
Dec.  =  -j-  29°  10'  06".     A  magnificent  cluster,  said  to  contain  not  less 
than  a  thousand  stars,  between  the  southern  Hound  and  the  knee  of 
Bootes. 

Discovered  by  Messier,  1764 ;  and  described  as  "  a  nebula  without  a 
star,  brilliant  and  round."     Resolved  by  Herschel,  1784,  with  his  20 
M2 


138  GEOGRAPHY   OF   THE   HEAVENS. 

feet  reflector,  who  calls  it  "  a  beautiful  cluster  of  stars,  5'  or  6'  in  diame- 
ter." I  have  repeatedly  examined  this  fine  object.  The  mass  of  stars 
is  greatly  compacted  together  at  the  center,  and  spread  out  in  brilliant 
radiations  in  all  directions.  The  largest  radiations  extend  downward,  as 
seen  with  an  inverting  eye-piece. 


CORONA    BOREALIS. 

THE  NORTHERN  CROWN. — This  beautiful  constella- 
tion may  be  easily  known  by  means  of  its  six  prin- 
cipal stars,  which  are  so  placed  as  to  form  a  circular 
figure,  very  much  resembling  a  wreath  or  crown. 
It  is  situated  directly  north  of  the  Serpent's  head, 
between  Bootes,  on  the  west,  and  Hercules,  on  the 
east. 

This  asterism  was  known  to  the  Hebrews  by  the  name  of  Ashtaroth  ; 
and  by  this  name  the  stars  in  Corona  Borealis  are  called,  in  the  East,  to 
this  day. 

Alphacca,  marked  o,  of  the  2d  magnitude,  is  the 
brightest  and  middle  star  in  the  diadem,  and  about 
11°  E.  of  Mirac,  in  Bootes.  It  is  very  readily  dis- 
tinguished from  the  others,  both  on  account  of  its 
position  and  superior  brilliancy.  Alphacca,  Arctu- 
rus  and  Seginus,  form  nearly  an  isosceles  triangle, 
the  vertex  of  which  is  at  Arcturus. 

This  constellation  contains  twenty-one  stars,  of 
which  only  six  or  eight  are  conspicuous;  and  most 
of  these  are  not  larger  than  the  third  magnitude. 
Its  mean  declination  is  30°  north,  and  its  mean 
right  ascension  235°.  Its  center  is,  therefore,  on 
the  meridian  about  the  last  of  June,  and  the  first 
of  July. 

"  And,  near  to  Helice,  effulgent  rays 
Beam,  Ariadne,  from  thy  starry  crown : 
Twenty  and  one  her  stars ;    but  eight  alone 
Conspicuous ;  one  doubtful,  or  to  claim 
The  second  order,  or  accept  the  third." 


CONSTELLATION  OF  LEO  MINOR.       139 

.f       ^ 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XIV. 

LEO  MINOR — THE  LITTLE  LION. 
LYNX — THE  LYNX. 

Favorably  situated  for  examination  in  March,  April 
and  May. 

LEO   MINOR. 

THE  LITTLE  LION. — This  constellation  was  formed 
by  Hevelius,  out  of  the  Stella  i?iformes,  or  unformed 
stars  of  the  ancients,  which  lay  scattered  between 
the  zodiacal  constellation  Leo,  on  the  south,  and 
Ursa  Major,  on  the  north.  Its  mean  right  ascension 
is  the  same  with  that  of  Regulus,  and  it  comes  to 
the  meridian  at  the  same  time,  on  the  6th  of  April. 

The  modern  constellations,  qr  those  which  have  been  added  to  our 
celestial  maps,  since  the  adoption  of  the  Greek  notation,  in  1603,  are 
referred  to  by  the  letters  of  the  English  alphabet,  instead  of  the  Greek. 
This  is  the  case  in  regard  to  Leo  Minor,  and  all  other  constellations 
whose  origin  is  subsequent  to  that  period. 

Leo  Minor  contains  fifty-three  stars,  including 
only  two  of  the  4th  magnitude.  The  principal  star 
is  situated  in  the  body  of  the  animal,  13°  north  of 
Gamma  Leonis,  in  a  straight  line  with  Phad,  and 
may  be  known  by  a  group  of  smaller  stars,  a  little 
above  it,  on  the  northwest. 

It  forms  an  equilateral  triangle  with  Gamma  and  Delta  Leonis,  the 
vertex  being  in  Leo  Minor.  This  star  is  marked  with  the  letter  /,  in 
modern  catalogues,  and,  being  the  principal  representative  of  the  constel- 
lation, is  itself  sometimes  called  the  Little  Lion :  8°  E.  of  this  star  (the 
Little  Lion),  are  two  stars  of  the  4th  magnitude,  in  the  last  paw  of  Ursa 
Major ;  and  about  10°  N.  W.  of  it,  are  two  other  stars,  of  the  3d  mag- 
nitude, in  the  first  hind  paw. 

"  The  Smaller  Lion  now  succeeds;  a  cohort 
Of  fifty  stars  attends  his  steps ; 
And  three,  to  sight  unarmed,  invisible." 


140  GEOGRAPHY  OF  THE   HEAVENS. 


TELESCOPIC    OBJECTS. 

200  HERSCHEL  I,  LEGISTS  MIDORIS. — A.  R.  =  8  h.  42  m.  44  s. 
Dec.  =  -f-  340  00'  06".  A  bright  oval  nebula,  between  Lynx  and 
Cancer. 

Discovered  by  Herschel,  1787  ;  and  registered  as  a  very  beautiful  ne- 
bula, 8'  long  and  3'  broad. 

Other  nebula  will  be  found  on  the  chart. 


THE    LYNX. 

THE  constellation  of  the  Lynx,  like  that  of  the 
Camelopard,  exhibits  no  very  interesting  features, 
by  which  it  can  be  distinguished.  It  contains  only 
a  moderate  number  of  inferior  stars,  scattered  over 
a  large  space,  north  of  Gemini  and  between  Auriga 
and  Ursa  Major.  The  whole  number  is  forty-four, 
including  only  three  that  are  so  large  as  the  4th 
magnitude.  The  largest  of  these,  in  the  nose, 
is  in  the  solstitial  colure,  14°  north  of  Menkalina, 
in  the  east  shoulder  of  Auriga.  The  other  two 
principal  stars  are  in  the  brush  of  the  tail,  3J°  south- 
west of  another  star,  of  the  same  brightness,  in  the 
mouth  of  the  Lesser  Lion,  with  which  it  makes  a 
small  triangle.  Its  center  is  on  the  meridian  at  9 
o'clock,  on  the  23d,  or,  at  half-past  7,  on  the  1st,  of 
February 

TELESCOPIC    OBJECTS. 

4  LYWCIS.— A.  R.  =  6  h.  07  m.  51  a.     Dec.  =  -|-  59°  25'  08". 
A  close  double  star,  in  the  nose  of  the  Lynx.     A  6,  B  7£. 
Discovered  by  Struve. 
Pos.  88056'         Dist  0".815         Epoch  1830.28     Struve. 

174  P.  VI,  LTNCIS.— A.  R.  =  6  h.  30  m.  42  s.  Dec.  -f-  59°  35' 
06".  A  double  star,  under  the  eye  of  the  Lynx.  A  7£,  white,  B  10, 
blue. 

Discovered  by  Struve. 

Pos.   133028'         Dist.  4".  197         Epoch  1830.58. 

The  companion  appears  to  be  variable,  ranging  from  8£  to  the  12th 
magnitude. 

14  LYNCIS.— A.  R.  6  h.  38  m.  57  s.     Dec.  =  59°  37'  06"    A  close 


CONSTELLATION  OF  THE  LYNX.  141 

double  star,  under  the  eye  of  the  Lynx.     A  5£,  "golden  yellow,"  B  1, 
"  purple." 

Discovered  bv  Struve. 

Pos.  50051'"         Dist.  0"897         Epoch  1830.88 

137.  HKRSCHKL  I,  LYNCIS.— A.  R.  =  09  h.  14  m.  32s.  Dec.  -f- 
35°  1 1'  09".  A  bright  nebula,  on  the  fore  paws  of  Leo  Minor,  but  in- 
cluded within  the  limits  of  the  Lynx. 

Discovered  by  Herschel,  in  !  786,  who  describes  it  as  round,  pale  white, 
and  sparkling  in  the  center,  with  an  additional  faint  nebulosity  surround- 
ing the  nucleus.  Some  3'  in  diameter. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATION   ON 

MAP     NO.     XV. 

LIBRA — THE  SCALES. 

Favorably  situated  for  examination  in  May,  June 
and  July. 

LIBRA. 

THE  BALANCE. — -This  is  the  seventh  sign,  and  eighth 
constellation,  from  the  vernal  equinox,  and  is  situ- 
ated in  the  Zodiac,  next  east  of  Virgo. 

The  sun  enters  this  sign,  at  the  autumnal  equi- 
nox, on  the  23d  of  September;  but  does  not  reach 
the  constellation  before  the  27th  of  October. 

Virgo  was  the  goddess  of  justice,  and  Libra,  the 
scales,  which  she  is  usually  represented  as  holding 
in  her  left  hand,  are  the  appropriate  emblems  of 
her  office.  When  the  sun  enters  the  sign  Libra,  the 
days  and  nights  are  equal  all  over  the  world,  and 
seem  to  observe  a  kind  of  equilibrium,  like  a  balance. 

When,  however,  it  is  said  that  the  vernal  and 
autumnal  equinoxes  are  in  Aries  and  Libra,  and  the 
tropics  in  Cancer  and  Capricorn,  it  must  be  remem- 
bered that  the  signs,  Aries  and  Libra,  Cancer  and 


142  GEOGRAPHY   OF  THE  HEAVENS. 

Capricorn,  and  not  the  constellations  of  these  na  nes, 
are  meant;  for  the.  equinoxes  are  now  in  the  con- 
stellations Pisces  and  Virgo,  and  the  tropics  in  Ge- 
mini and  Sagittarius  ;  each  constellation  having  gone 
forward  one  sign  in  the  ecliptic. 

About  twenty-two  centuries  ago,  the  constellation 
Libra  coincided  with  the  sign  Libra;  but,  having 
advanced  30°,  or  more,  in  the  ecliptic,  it  is  now  in 
the  sign  Scorpio,  and  the  constellation  Scorpio  is  in 
the  sign  Sagittarius,  and  so  on. 

While  Aries  is  now  advanced  a  whole  sign  above 
the  equinoctial  point,  into  north  declination,  Libra 
has  descended  as  far  below  it.  into  south  declination. 

Libra  contains  fifty-one  stars,  including  two  of 
the  2d  magnitude,  and  several  of  the  4th.  Its  mean 
declination  is  8°  south,  and  its  mean  right  ascension 
226°.  Its  center  is,  therefore,  on  the  meridian  about 
the  22d  of  June. 

It  may  be  known  by  means  of  its  four  principal 
stars,  forming  a  quadrilateral  figure,  lying  north- 
east and  southwest,  and  having  its  upper  and  lower 
corners  nearly  in  a  line  running  north  and  south. 
The  two  stars  which  form  the  northeast  side  of  the 
square  are  situated  about  7°  apart,  and  distinguish 
the  northern  scale.  The  two  stars  which  form  the 
southwest  side  of  the  square  are  situated  about  6° 
apart,  and  distinguish  the  southern  scale. 

Zubeneschamali,  marked  $,  in  the  northern  scale,  about  21°  E.  of 
Spica,  and  8°  E.  of  Lambda  Virginis,  is  a  star  of  the  2d  magnitude,  and 
is  situated  very  near  the  ecliptic,  about  42^°  E.  of  the  autumnal  equinox. 
The  distance  from  this  star  down  to  Theta  Ceutauri,  is  about  ti3°,  with 
which,  and  Spica  Virginis,  it  forms  a  large  triangle,  on  the  right. 

Zubenelgemabi,  marked  a.,  is  also  of  the  2d  magnitude,  9^o  below 
Zubeneschamali,  towards  the  southwest,  and  it  comes  to  the  meridian 
about  twenty-six  minutes  after  it,  on  the  23d  of  June.  Zubenelgemabi 
is  the  northernmost  of  the  four  bright  stars  in  this  figure,  and  is  exactly 
opposite  the  lower  one,  which  is  1 1°  S.  of  it. 

The  star  marked  y,  is  a  star  of  the  3d  magnitude,  in  the  north- 
ern scale,  7°  S.  E.  of  Zubenelgemabi,  and  nearly  opposite  to  Zubenes- 
chamali, at  the  distance  of  11°  on  the  east.  These  two  make  the 
diagonal  of  the  square  east  and  west. 


CONSTELLATION  OF  LIBRA.  143 

Ma  is  a  star  of  the  4th  magnitude,  and  constitutes  the  southernmost 
c<  ner  of  the  square.  It  is  about  6°  S.  E.  of  Zubeneschamali,  and  1  1° 
8  of  Zubenelgemabi,  with  which  it  forms  the  other  diagonal,  north  and 
so  ith. 

Zubenelgubi  is  a  star  of  the  2d  magnitude,  situated  below  the  southern 
scale,  at  the  distance  of  6°  from  Iota,  and  marks  the  southern  limit  of  the 
Zodiac.  It  is  situated  in  a  right  line  with,  and  nearly  midway  between, 
Spica  Virginis  and  Beta  Scorpii  ;  —  and  comes  to  the  meridian  nearly 
at  the  same  moment  with  Nekkar,  in  the  head  of  Boutes. 

The  remaining  stars  in  the  constellation  are  too  small  to  engage 
attention. 

The  scholar,  in  tracing  out  this  constellation  hi  the  heavens,  will  per- 
ceive that  Lambda  and  Mu,  which  lie  in  the  feet  of  Virgo,  on  the  west, 
form,  with  Zubeneschamali  and  Zubenelgemabi,  almost  as  handsome  and 
perfect  a  figure  as  the  other  two  stars  in  the  Balance  do,  on  the  east. 

TELESCOPIC     OBJECTS. 

A  DOUBLE  STAR.—  A.  R.  =  14  h.  14  m.  1  1  s.  Dec.  =  —  07°  01' 
07".  —  15°,  east  by  north,  from  Spica  Virginis.  The  stars  are  equal,  and 
of  the  8th  magnitude 

Pos.  160008'         Dist.  5".02         Epoch  1836.44     Smyth. 

A  CLOSE  DOUBLE  STAU  .—  A.  R.  =  14  h.  16  m.   06  s.      Dec.  10° 
56'  03".  —  Close  to  the  heel  of  the  Virgin.     A  7£,  yellow,  B  9£,  greenish. 
Discovered  by  Strive,  ,1827. 
Pos.  3260  87'         Dist.   1".41         Epoch  1829.83. 

A  CLOSELY  COMPACTED  CLUSTER.  —  A.  R.  =  15  h.  10m.  26s, 
Dec.  =  -f-  020  41'  03".  Over  the  Balance. 

Discovered  by  Messier,  1764,  who  registers  it  as  a  round  nebula,  in 
which,  he  is  confident,  not  a  star  exists;  and  yet,  in  May,  1791,  Sir 
William  Herschel,  by  the  aid  of  his  40  feet  reflector,  counted  in  this  ob- 
ject no  less  than  200  stars 

This  is  one  of  the  great  clusters  comparatively  near  our  sidereal  stra- 
tum, and  somewhat  resembling  that  in  Hercules,  hereafter  described  and 
figured.  The  drawing  was  made  under  a  power  of  280,  and  12  inches 
aperture,  the  object  was  thus  described. 


g  OR  51  LiBna:.  —  A.  R.  =  15  h.  58  m.  35  s.  Dec.  =  —  10°  55 
06  .  A  most  elegant  triple  star,  between  the  upper  scale  of  Libra  and 
the  right  leg  of  Ophiuchus.  A  4£,  B  5,  magnitude. 

Pos.  A  B  187°  56'        Dist.  1"  .50         Epoch  1782.36?  „       ,    , 
AC    88    37  6     .38  1  780.39  5  HerscheL 

AB355    58  1  .147  1825.487  -,  .. 

A  C    78    36  6     .75  -      5  otruve- 

A  B    16    43  1     .28  1841.48 

AC    74    40  6     .75  - 

A  B    24    52  0    .97  1846.48     „..  ,   , 

AC    74    42  7     .16  -  -      5  MltcneL 

The  disks  are  perfect,  with  a  power  of  600  times, 


144  GEOGRAPHY  OF  THE   HEAVENS. 

A  LARGE  COMPRESSED-  CLUSTER. — A.  R.  =  15  h.  08  m.  06  s. 
Dec.  =  —  20°  26'  07". 

Discovered  by  Herschel,  1785.  It  forms  a  sort  of  connecting  link  be- 
tween the  congeries  of  stars  and  the  distant  nebulae. 


• 
DIRECTIONS  FOR  TRACING  THE  CONSTELLATION  ON 

MAP    NO.    XVI. 

SCORPIO — THE  SCORPION. 

Favorably  situated  for  examination  in  June,  July, 
and  August. 

SCORPIO. 

THE  SCORPION. — This  is  the  eighth  sign,  and  ninth 
constellation,  in  the  order  of  the  Zodiac.  It  pre- 
sents one  of  the  most  interesting  groups  of  stars, 
for  the  pupil  to  trace  .out,  that  is  to  be  found  in  the 
southern  hemisphere.  It  is  situated  southward  and 
eastward  of  Libra,  and  is  on  the  meridian  the  10th 
of  July. 

The  sun  enters  this  sign  on  the  23d  of  October,  but  does  not  reach 
the  constellation  before  the  20th  of  November.  W  hen  astronomy  was 
first  cultivated  in  the  East,  the  two  solstices  and  the  two  equinoxes  took 
place  when  the  sun  was  in  Aquarius  and  Leo,  Taurus  and  Scorpio, 
respectively. 

Scorpio  contains,  according  to  Flamsted,  forty- 
four  stars;  including  one  of  the  1st  magnitude,  one 
of  the  2d,  and  eleven  of  the  3d.  It  is  readily  dis- 
tinguished from  all  others,  by  the  peculiar  luster 
and  the  position  of  its  principal  stars. 

Antares,  marked  a,  is  the  principal  star,  and  is 
situated  in  the  heart  of  the  Scorpion,  about  19°  E. 
of  Zubenelgubi,the  southernmost  star  in  the  Balance. 
Antares  is  the  most  brilliant  star  in  that  region  of 


CONSTELLATION  OF  SCORPIO.  145 

the  skies,  and  may  be  otherwise  distinguished  by 
its  remarkably  red  appearance.  Its  declination  is 
about  26°  S.  It  comes  to  the  meridian  about  three 
hours  after  Spica  Virginis,  or  fifty  minutes  after 
Corona  Borealis,  on  the  10th  of  July.  It  is  one  of 
the  stars  from  which  the  moon's  distance  is  reck- 
oned, for  computing  the  longitude  at  sea. 

There  are  four  great  stars  in  the  heavens,  Fomalhaut,  Aldebaran, 
Regulus,  and  Antares,  which  formerly  answered  to  the  solstitial  and 
equinoctial  points,  and  which  were  much  noticed  by  the  astronomer*  of 
the  East 

About  8£°  N.  W.  of  Antares,  is  a  star  of  the  2d 
magnitude,  in  the  head  of  the  Scorpion,  called 
Grqffias,  marked  ^3.  It  is  but  1°  N.  of  the  earth's 
orbit.  It  may  be  recognized  by  means  of  a  small 
star,  situated  about  1°  N.  E.  of  it,  and  also  by  its 
forming  a  slight  curve  with  two  other  stars  of  the 
3d  magnitude,  situated  below  it,  each  about  3° 
apart.  The  broad  part  of  the  constellation  near 
Graffias  is  powdered  with  numerous  small  stars, 
converging  down  to  a  point  at  Antares,  and  resem- 
bling in  figure  a  boy's  kite. 

As  you  proceed  from  Antares,  there  are  ten  con- 
spicuous stars,  chiefly  of  the  3d  magnitude,  which 
mark  the  tail  of  the  kite,  extending  down,  first  in 
a  south-southeasterly  direction,  about  17°,  thence 
easterly,  about  8°  further,  when  they  turn,  and  ad- 
vance about  8°  towards  the  north,  forming  a  curve, 
like  a  shepherd's  crook,  or  the  bottom  part  of  the 
letter  S.  This  crooked  line  of  stars,  forming  the 
tail  of  the  Scorpion,  is  very  conspicuous,  and  may 
be  easily  traced. 

The  first  star  below  Antares,  which  is  the  last  in  the  back,  is  of  only 
the  4th  magnitude.  It  is  about  2°  S.  E.  of  Antares,  and  is  marked  T. 

Epsilon,  of  the  3d  magnitude,  is  the  second  star  from  Antares,  and  the 
first  in  the  tail.  It  is  situated  about  7°  below  the  star  T,  but  inclining  a 
little  to  the  east 

Mu,  of  the  3d  magnitude,  is  the  3d  star  from  Antares.     It  is  situated 

N 


146  GEOGRAPHY  OF  THEl  HEAVENS. 

4£°  below  Epsilon.  It  may  otherwise  be  known  by  means  of  a  small 
star  close  by  it,  on  the  left. 

Zetay.  of  about  the  same  magnitude,  and  situated  about  as  far  below 
Mu,  is  the  fourth  star  from  Antares.  Here  the  line  turns  suddenly  to 
the  east. 

Eta,  also  of  the  3d  magnitude,  is  the  fifth  star  from  Antares,  and  about 
3£°  east  of  Zeta. 

Theta,  of  the  same  magnitude,  is  the  sixth  star  from  Antares,  and 
about  4$°  E.  of  Eta.  Here  the  line  turns  again,  curving  to  the  north, 
and  terminates  in  a  couple  of  stars. 

lota,  is  the  seventh  star  from  Antares,  3£°  above  Theta,  curving  a  lit- 
tle to  the  left.  It  is  a  star  of  the  3d  magnitude,  and  may  be  known  by 
means  of  a  small  star  almost  touching  it.  on  the  east. 

Kappa,  a  star  of  equal  brightness,  is  less  than  2°  above  Iota,  and  a 
little  to  the  right. 

Lesuth,  of  the  3d  magnitude,  is  the  brightest  of  the  two  last  in  the  tail, 
and  is  situated  about  3°  above  Kappa,  still  further  to  the  right.  It  may 
readily  be  known  by  means  of  a  smaller  star  close  by  it,  on  the  west 

This  is  a  very  beautiful  group  of  stars,  and  easily 
traced  out  in  the  heavens.  It  furnishes  striking 
evidence  of  the  facility  with  which  most  of  the  con- 
stellations may  be  so  accurately  delineated  as  to 
preclude  every  thing  like  uncertainty  in  the  knowl- 
edge of  their  relative  situation. 

"  The  heart,  with  luster  of  amazing  force, 
Refulgent  vibrates;  faint  the  other  parts, 
And  ill-defined  by  stars  of  meaner  note." 

TELESCOPIC     OBJECTS. 

ANTARES,  OR  a.  SCORPII.— A.  R.  =  16 h.  19  m.  36  s.  Dec.  =  — 
260  04'  03". 

Discovered  to  be  double,  at  the  Cincinnati  Observatory,  July,  1845. 
A  1,  orange,  B  12,  blue.  The  contrast  of  color  is  distinctly  marked. 
The  small  star  follows  the  principal  one.  on  the  same  parallel.  Distance 
2". 5.  The  principal  star  was  pronounced  to  be  double,  by  the  Wash- 
ington observers,  in  August,  1846,  but  this  error  has  been  subsequently 
corrected.  This  forms  the  most  remarkable  double  star  now  on  the  cata- 
logues,— there  being  no  star  of  the  1st  magnitude  known,  having  so  minute 
a  companion,  at  so  short  a  distance. 

It  was  first  divided  with  a  power  of  250,  and  aperture  of  12  niches. 
The  best  power  for  measures  is  500,  with  an  aperture  reduced  to  9 
inches.  My  measures  indicate  a  slight  increase  in  the  distance  between 
the  two  components.  This,  however,  requires  confirmation. 

v  SCORPII.=A.  R.  =  16  h.  02  m.  42  s.  Dec.  =  —  19°  02'  03". 
Registered  as  a  double  star.  Discovered  to  be  triple,  at  the  Cincinnati 


CONSTELLATION  OF  SCORPIO.  147 

t 

Observatory,  1846.     A  and  B  nearly  equal,  and  of  the  6th  magnitude; 
C  7,  magnitude. 
Distance  from  A  to  B  =  I ".2         From  A  -f-  B  to  C  40".00 

~~2~~ 
Pos.   A  -f-  B  to  C  =  3380  29' 

2 -'V 

From  A  to  B  =  37    57 

This  star  was  first  seen  double  by  Herschel,  in  1779  ;  but  its  great 
southern  declination  brought  it  too  near  the  horizon,  in  the  latitude  of  his 
observatory,  to  see  the  close  star?:  The  same  may  be  said  of  Antares. 
I  have  recently  received  intelligence,  that  measures  of  Antares  have  been 
made  in  England,  1847. 

a-  SCORPH.— A.  R.  =  16  h.  llm.  28  s.  Dec.  =  —  25°  12'  02". 
A  delicate  double  star,  2°  W.  by  N.  from  Antares.  A  4,  B  9^,  mag. 
Pos.  271°  05'  Dist.  20".  04 

Discovered  by  Herschel,  1783.  There  is  no  evidence  of  any  change 
in  the  relative  position  ot  the  components. 

Pos.  2710  05'         Dist.  22". 34         Epoch  1817.60  'Mitchel. 

£  SCORPII— A.  R.  =  15  h.  56  m.  18  s.  Dec.  =  —  19°  21'  07". 
A  second  rate  Greenwich  star.  Discovered  to  be  double  by  Herschel, 
1779.  A  2,  B  5^,  magnitude.  -Miidler  thinks  this  a  binary  system  of 
long  period.  The  measures  are  as  follow : 

Pos.  25009'         Dist.    I4".37         Epoch  1779  72     Herschel. 

26    30  13  .65  1823.28     Her.  &  South. 

My  own  measures  are : 

Pos.  260  22'  Dist.  13".68  Epoch  1846  50.  Agreeing  nearly 
with  Herschel  and  South. 

The  Bedford  Catalogue  gives : 

Pos.  24009'         Dist.  13".0l         Epoch  1835.39. 

From  these  measures,  there  is  very  little  evidence  of  any  change,  either 
in  distance  or  angle  of  position. 

A  LARGE  AND  BRILLIANT  CLUSTER. — A.  R.  =  16  h.  07  m.  28  s. 
Dec.  —  220  35'  04". 

Discovered  by  Messier,  in  17SO,  who  describes  it  as  resembling  the 
nucleus  of  a  comet.  It  is  4°  E.  of  /  Scorpii.  and  midway  between  A 
and  /g.  It  is  remarkable  as  being  located  on  the  western  edge  of  an  im- 
mense opening,  or  vacant  spot,  in  the  heavens,  of  4°  in  breadth,  in  which 
the  most  powerful  telescopes  reveal  no  st  irs !  The  center  of  this  cluster 
is  very  brilliant,  ana  the  surrounding  points  of  light  profusely  scattered 
Herschel  regards  it  as  one  of  the  richest  and  most  condensed  masses  of 
stars  yet  discovered  in  the  heavens.  Examined  and  figured,  2d  August, 
1847. 

A  SMALL  COMPRESSED  CLUSTER. — A.  R.  =  16  h.  13  m.  51  s. 
Dec.  =  —  26°  07'  05".  It  precedes  Antares  l^o  on  the  same  parallel. 

Discovered  by  Messier.  Resolved  by  Herschel;  who  estimates  its 
profundity  of  the  344th  order. 


148  GEOGRAPHY  OF  THE   HEAVENS. 

This  condensed  group  is  also  on  the  western  edge  of  the  opening 
above  referred  to,  and  has  given  rise  to  the  following  remarks  by  Arago. 
referring  to  the  idea  expressed  by  Herschel,  that,  wherever  chasms  in  the 
heavens  are  found,  near  by,  extensive  clusters  and  nebula  will  be 
discovered. 

"  Let  us,"  says  M  A  rago,  "  connect  these  facts  with  the  observation 
which  has  shown  that  the  stars  are  greatly  condensed  toward  the  center 
of  the  spherical  clusters,  and  with  that  which  has  afforded  the  proof  that 
these  stars  sensibly  obey  a  certain  power  of  condensation  (or  clustering 
power),  and  we  shall  feel  disposed  to  admit,  with  Herschel,  that  nebulfe 
are  formed  sometimes,  by  the  incessant  operation  of  a  great  number  of 
ages,  at  the  expense  of  the  scattered  stars  which  originally  occupied  the 
surrounding  regions ;  and  the  existence  of  empty  or  ravaged  spaces — to 
use  the  picturesque  expression  of  the  great  astronomer,  will  no  longer 
present  any  thing  which  will  confound  the  imagination  " 

A  LARGE  RESOLVABLE  NEBULA. — A.  R.  =  16  h.  51  m.  04  s.  Dec. 
—290  50'  06". 

Discovered  by  Messier.  Resolved  by  Herschel ;  who  estimates  its  dis- 
tance to  be  of  the  73  Ith  order.  It  resembles  a  comet,  and  has  been 
reported  as  such,  at  least  once,  in  a  very  public  manner. 

All  the  reported  clusters  hi  this  constellation  are  readily  detected  by 
any  ordinary  telescope.  Their  resolution  does  not  require  a  high  power. 
But  to  show  them  in  all  their  richness  and  brilliancy,  a  powerful  instru- 
ment is  necessary. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XVII. 

URSA  MINOR — THE  LESSER  BEAR. 

CEPHEUS. 

CAMELOPARDUS — THE  CAMELOPARD. 

Favorably  situated  for  examination  in  March,  April, 
and  May. 

URSA    MINOR. 

THE  LITTLE  BEAR. — This  constellation,  though  not 
remarkable  in  its  appearance,  and  containing  but 
few  conspicuous  stars,  is,  nevertheless,  justly  dis- 
tinguished from  all  others,  for  the  peculiar  advan- 
tages which  its  position  in  the  heavens  is  well 
known  to  afford  to  nautical  astronomy,  and  espe- 
cially to  navigation  and  surveying. 


CONSTELLATION  OF  URSA  MINOR.  14il 

The  stars  in  this  group  being  situated  near  the 
celestial  pole,  appear  to  revolve  about  it,  very 
slowly,  and  in  circles  so  small  as  never  to  descend 
below  the  horizon. 

In  all  ages  oi  the  world,  this  constellation  has 
been  more  universally  observed,  and  more  carefully 
noticed  than  any  other,  on  account  of  the  import- 
ance which  mankind  early  attached  to  the  position 
of  its  principal  star. 

This  star,  which  is  so  near  the  true  pole  of  the 
heavens,  has  from  time  immemorial,  been  denomi- 
nated the  NORTH  POLAR  STA^.  By  the  Greeks  it  is 
called  Cynosure  :  by  the  Romans,  Cynosum,  and  by 
othes  nations,  Alruccabah. 

It  is  of  the  3d  magnitude,  or  between  the  2d  and 
3d,  and  situated  a  little  more  than  a  degree  and  a 
half  from  the  true  pole  of  the  heavens,  on  that  side 
of  it  which  is  towards  Cassiopeia,  and  opposite  to 
Ursa  Major.  Its  position  is  pointed  out  by  the 
direction  of  the  two  Pointers,  Merak  and  Dubhe, 
which  lie  in  the  square  of  Ursa  Major.  A  line  join- 
ing £  Cassiopeia,  which  lies  at  the  distance  of  32° 
on  one  side,  and  Megrez,  which  lies  at  the  same  dis- 
tance on  the  other  side,  will  pass  through  the  polar 
star. 

So  general  is  the  popular  notion,  that  the  North 
Polar  Star  is  the  true  pole  of  the  world,  that  even 
surveyors  and  navigators,  who  have  acquired  con- 
siderable dexterity  in  the  use  of  the  compass  and  the 
quadrant,  are  not  aware  that  it  ever  had  any  devia- 
tion, and  consequently  never  make  allowance  for 
any.  All  calculations  derived  from  the  observed 
position  of  this  star,  which  are  founded  upon  the 
idea  that  its  bearing  is  always  due  north  of  any 
place,  are  necessarily  erroneous,  since  it  is  in  this 
position  only  twice  in  twenty-four  hours;  once 
when  above,  and  once  when  below  the  pole. 

According  to  the  Nautical  Almanac,  the  mean  dis- 

N2 


150  GEOGRAPHY   OF    THE   HEAVENS. 

tance  of  this  star  from  the  true  pole  of  the  heavens, 
for  the  1st  Jan.  1849,  is  1°  29'  28",  and  its  mean  right 
ascension  is  1  h.  5  m.  and  10.60s.  Consequently, 
when  the  right  ascension  of  the  meridian  of  any 
place  is  1  h.  5  m.  and  10.66  s.  the  star  will  be 
exactly  on  the  meridian  at  that  time  and  place,  but 
1°  29'  28"  above  the  true  pole.  Six  hours  after,  when 
the  right  ascension  of  the  meridian  is  7  h.  5  m.  and 
10.66  s.  the  star  will  be  at  its  greatest  elongation, 
or  1°  29'  28"  directly  west  of  the  true  pole,  and  par- 
allel to  it,  with  respect  to  the  horizon  ;  and  when 
the  right  ascension  o£the  meridian  is  13  h.  5  m.  and 
10.66s.  the  star  will  be  again  on  the  meridian, 
but  at  the  distance  of  1°  29'  28"  directly  below  the 
pole. 

In  like  manner,  when  the  right  ascension  of  the 
meridian  is  19  h.  5m.  and  10.66s.  the  star  will 
be  at  its  greatest  eastern  elongation,  or  1°  29'  28" 
east  of  the  true  pole ;  and  when  it  has  finished  its 
revolution,  and  the  right  ascension  of  the  meridian 
is  25  h.  5  m.  and  10.66  s.  or,  what  is  the  same 
thing,  1  h.  5  m.  and  10.66  s.  the  star  will  now  be 
on  the  meridian  again,  1°  29'  28"  above  the  pole. 

N.  13.  The  right  ascension  of  the  meridian  or  of  the  midheaven,  is 
the  distance  of  the  lirst  point  of  Aries  from  the  meridian,  at  the  time  and 
place  of  observation.  The  right  ascension  of  the  meridian  for  any  time, 
is  found,  by  adding  to  the  given  time  the  sun's  right  ascension  at  the  same 
time,  and  deducting  24  hours,  when  the  sum  exceeds  24  hours. 

From  the  foregoing  facts  we  learn,  that  from  the 
time  the  star  is  on  the  meridian,  above  the  pole,  it 
deviates  farther  and  farther  from  the  true  meridian, 
every  hour,  as  it  moves  to  the  west,  for  the  space  of 
six  hours,  when  it  arrives  at  its  greatest  elongation 
west,  whence  it  reapproaches  the  same  meridian 
below  the  pole,  during  the  next  six  hours,  and  is^ 
then  again  on  the  meridian;  being  thus  alternately 
half  the  time  west  of  the  meridian,  and  half  the 
time  east. of  it. 


CONSTELLATION  OF  URSA  MINOR.       151 

Hence,  it  is  evident  that  the  surveyor  who  regu- 
la  es  his  compass  by  the  North  Polar  Star,  mast 
take  his  observation  when  the  star  is  on  the  merid- 
ian, either  above  or  below  the  pole,  or  make  allow- 
ance for  its  altered  position  in  every  other  situation. 
For  the  same  reason  must  the  navigator,  who  ap- 
plies his  quadrant  to  this  star  for  the  purpose  of 
determining  the  latitude  he  is  in,  make  a  similar 
allowance,  according  as  its  altitude  is  greater  or 
less  than  the  true  pole  of  the  heavens  ;  for  we  have 
seen  that  it  is  alternately  half  the  time  above  and 
half  the  time  below  the  pole. 

The  method  of  finding  the  latitude  of  a  place 
from  the  altitude  of  the  polar  star,  as  it  is  quite  sim- 
ple, is  very  often  resorted  to.  Indeed,  in  northern 
latitudes,  the  situation  of  this  star  is  more  favorable 
for  this  purpose  than  that  of  any  other  of  the  heav- 
enly bodies,  because  a  single  observation,  taken  at 
any  hour  of  the  night,  with  a  good  instrument,  will 
give  the  true  latitude,  without  any  calculation  or 
correction,  except  that  of  its  polar  aberration. 

If  the  polar  star  always  occupied  that  point  in  the  heavens  which  is 
directly  opposite  to  the  north  pole  of  the  earth,  it  would  be  easy  to  under- 
stand how  latitude  could  be  determined  from  it  in  the  northern  hemisphere ; 
for  in  this  case,  to  a  person  on  the  equator,  the  poles  of  the  world  would 
be  seen  in  the  horizon.  Consequently,  the  star  would  appear  just  visible 
in  the  northern  horizon,  without  any  elevation.  Should  the  person  now 
travel  one  degree  towards  the  north,  he  would  see  one  degree  below  the 
Star,  and  he  would  think  it  had  risen  one  degree. 

And  since  we  always  see  the  whole  of  the  upper  hemisphere  at  one 
view,  when  there  is  nothing  in  the  horizon  to  obstruct  our  vision,  it  fol- 
lows that  if  we  should  travel  10°  north  of  the  equator,  we  should  see 
just  10°  below  the  pole,  which  would  then  appear  to  have  risen  10°; 
and  should  we  stop  at  the  42d  degree  of  north  latitude,  we  should,  in  like 
manner,  have  our  horizon  just  42°  below  the  pole,  or  the  pole  would  ap- 
pear to  have  an  elevation  of  42°.  Whence  we  derive  this  general  truth: 
Tfte  elevation  of  the  pole  of  the  equator,  is  always  equal  to  the  latitude 
of  the  place  of  observation. 

Any  instrument,  then,  which  will  give  us  the  altitude  of  the  north 
pole,  will  give  us  also  the  latitude  of  the  place. 

The  method  of  illustrating  this  phenomenon,  as  given  in  most  treatises 
on  the  globe,  and  as  adopted  by  teachers  generally,  is  to  tell  the  scholar 


152  GEOGRAPHY  OF  THE  HEAVENS. 

that  the  north  pole  rises  higher  and  higher,  as  he  travels  farther  and 
farther  towards  it.  In  other  words,  whatever  number  of  degrees  he  ad- 
vances towards  the  north  pole,  so  many  degrees  will  it  rise  above  his 
horizon.  This  is  not  only  an  obvious  error  in  principle,  but  it  misleads 
the  apprehension  of  the  pupil.  It  is  not  that  the  pole  is  elevaled,  but 
that  our  horizon  is  depressed  as  we  advance  towards  the  north.  The 
same  objection  lies  against  the  artificial  globe ;  for  it  ought  to  be  so  fixed 
that  the  horizon  might  be  raised. or  depressed,  and  the  pole  remain  in  its 
own  invariable  position. 

Ursa  Minor  contains  twenty-four  stars,  including 
three  of  the  3d  magnitude  and  four  of  the  4th. 
The  seven  principal  stars  are  so  situated  as  to  form 
a  figure  very  much  resembling  that  in  the  Great 
Bear,  only  that  the  Dipper  is  reversed,  and  about 
one  half  as  large  as  the  one  in  that  constellation. 

The  first  star  in  the  handle,  called  Cynosura,  or 
Alruccabah,  is  the  polar  star,  around  which  the  rest 
constantly  revolve.  The  two  last  in  the  bowl  of 
the  Dipper,  corresponding  to  the  Pointers  in  the 
Great  Bear,  are  of  the  3d  magnitude,  and  situated 
about  15°  from  the  pole.  The  brightest  of  them 
is  called  Kochab,  which  signifies  an  axle  or  hinge, 
probably  in  reference  to  its  moving  so  near  the 
axis  of  the  earth. 

Kochab  may  be  easily  known  by  its  being  the 
brightest  and  middle  one  of  three  conspicuous  stars 
forming  a  row,  one  of  which  is  about  2°,  and  the 
other  3°,  from  Kochab.  The  two  brightest  of  these 
are  situated  in  the  breast  and  shoulder  of  the 
animal,  about  3°  apart,  and  are  called  the  Guards 
or  Pointers  of  Ursa  Minor.  They  are  on  the  meri- 
dian about  the  20th  of  June,  but  may  be  seen  at  all 
hours  of  the  night,  when  the  sky  is  clear. 

Of  the  four  stars  which  form  the  bowl  of  the 
Dipper,  one  is  so  small  as  hardly  to  be  seen.  They 
lie  in  a  direction  towards  Gamma  in  Cepheus;  but 
as  they  are  continually  changing  their  position  in 
the  heavens,  they  may  be  much  better  traced  out 
from  the  map,  than  from  description. 


CONSTELLATION  OF  URSA  MINOR.       153 

Kochab  is  about  25°  distant  from  Benetnasch, 
and  about  24°  from  Dubhe,  and  hence  forms  with 
them  a  very  nearly  equilateral  triangle. 

"  The  Lesser  Bear 

Leads  from  the  pole  the  lucid  band ;  the  stars 
Which  form  this  constellation,  faintly  shine, 
Twice  twelve  in  number ;  only  one  beams  forth 
Conspicuous  in  high  splendor,  named  by  Greece 
The  Cynosure,-  by  us  the  POLAH  STAR." 

The  following  stars  have  small  telescopic  com- 
panions :  a  or  the  pole  star.  0  or  Kochab,  the 
right  hand  upper  star  in  the  bowl  of  the  little 
dipper.  £  The  left  hand  upper  star  in  the  bow). 
The  companion  discovered  1841,  by  Prof.  Challis, 
with  the  Northumberland  equatorial,  at  Cambridge, 
England.  *  The  star  near  the  root  of  the  tail. 
Companion  12th  magnitude,  pale  blue.  8  The  star 
next  but  one  to  Polaris,  in  the  tail.  The  principal 
star  is  of  a  greenish  tinge,  while  the  companion  is 
grey.  There  are  a  few  faint  nebulae  in  this  con- 
stellation. 

CEPHEUS. 

CEPHEUS  is  represented  on  the  map  as  a  king,  in 
his  royal  robe,  with  a  scepter  in  his  left  hand,  and 
a  crown  of  stars  upon  his  head.  He  stands  in  a 
commanding  posture,  with  his  left  foot  over  the 
pole,  and  his  scepter  extended  towards  Cassiopeia, 
as  if  for  favor  and  defense  of  the  queen. 

"  Cepheus  illumes 

The  neighboring  heavens ;  still  faithful  to  his  queen, 
With  thirty-five  faint  luminaries  mark'd." 

This  constellation  is  about  25°  N.  W.  of  Cas- 
siopeia, near  the  2d  coil  of  Draco,  and  is  on  the 
meridian  at  8  o'clock  the  3d  of  November;  but  it 
will  linger  near  it  for  many  days.  Like  Cassiopeia, 
it  may  be  seen  at  all  hours  of  the  night,  when  the 
sky  is  clear,  for  to  us  it  never  sets. 


154  GEOGRAPHY  OF  THE  HEAVENS. 

By  reference  to  the  lines  on  the  map,  which  all  meet  in  the  pole,  it 
will  be  evident  that  a  star,  near  the  pole,  moves  over  a  much  lts&  spai  e 
in  one  hour,  than  one  at  the  equinoctial ;  and  generally,  the  nearer  the 
pole,  the  narrower  the  space,  and  the  slower  the  motion. 

The  stars  that  are  so  near  the  pole,  may  be  better  described  by  their 
polar  distance,  than  by  their  declination.  By  polar  distance,  is  meant — 
the  distance  from  the  pole ;  and  is  what  the  declination  wants  of  90°. 

In  this  constellation  there  are  35  stars  visible  to 
the  naked  eye;  of  these,  there  glitters  on  the 
shoulder,  a  star  of  the  3d  magnitude,  called  Alder- 
afnin,  marked  a,  which  with  two  others  of  the  same 
brightness,  8°  and  12°  degrees  apart,  form  a  slightly 
curved  line  towards  the  N.  E.  The  last,  whose  letter 
name  is  Kappa,  is  in  the  right  knee,  19°  N.  of  Caph, 
in  Cassiopeia.  The  middle  one  in  the  line,  is 
Alphirk,  marked  j3,  in  the  girdle.  This  star  is  one- 
third  of  the  distance  from  Alderamin  to  the  pole, 
and  nearly  in  the  same  right  line. 

It  cannot  be  too  well  understood  that  the  bearings,  or  directions  of 
one  star  from  another,  as  given  in  this  treatise,  are  strictly  applicable  only 
when  the  former  one  is  on,  or  near  the  meridian.  The  bearings  given, 
in  many  cases,  are  the  least  approximations  to  what  appears  to  be  their 
relative  position ;  and  in  some,  if  relied  upon,  will  lead  to  errors.  For 
example  :-i-It  is  said,  in  the  preceding  paragraph,  that  Kappa,  in 
Cepheiis,  bears  19°  N.  of  Caph  in  Cassiopeia.  This  is  true,  when 
Caph  is  on  the  meridian,  but  at  this  very  moment,  while  the  author  is 
writing  this  line,  Kappa  appears  to  be  19°  due  west  of  Caph ;  and  six 
months  hence,  will  appear  to  be  the  same  distance  east  of  it.  The 
reason  is  obvious ;  the  circle  which  CepheuS  appears  to  describe  about 
the  pole,  is  within  that  of  Cassiopeia,  and  consequently  when  on  the 
east  of  the  pole,  will  be  within,  or  between  Cassiopeia  and  the  pole — 
that  is.  west  of  Cassiopeia.  And  for  the  same  reason,  when  Cephe^s 
is  on  the  west  side  of  the  pole,  it  is  between  that  and  Cassiopeia,  or 
east  of  it. 

Let  it  also  be  remembered,  that  in  speaking  of  the  pole,  which  we 
shall  have  frequent  occasion  to  do,  in  the  course  of  this  work,  the  North 
Polar  Star,  or  an  imaginary  point  very  near  it,  is  always  meant ;  and 
not  as  some  will  vaguely  apprehend,  a  point  in  the  horizon,  directly  N. 
of  us.  The  true  pole  of  the  heavens,  is  always  elevated  just  as  many 
degrees  above  our  horizon,  as  we  are  north  of  the  Equator.  If  we  live 
in  42°  N.  latitude,  the  N.  pole  will  be  42°  above  our  horizon.  (See 
North  Polar  Star.) 

There  are  also  two  smaller  stars  about  9°  E.  of 


CONSTELLATION  OF  CEPHEUS.         155 

Alderamin  and  Alphirk,  with  which  they  form  a 
square;  Alderamin  being  the  upper,  and  Alphirk 
the  lower  one  on  the  W.  8°  apart.  In  the  center 
of  this  square  there  is  a  bright  dot,  or  semi- 
visible  star. 

The  head  of  Cepheus,  is  in  the  Milky-Way,  and 
may  be  known  by  three  stars  of  the  4th  magnitude 
in  the  crown,  which  form  a  small  acute  triangle, 
about  9°  to  the  right  of  Alderamin.  The  mean 
polar  distance  of  the  constellation  is  25°,  while  that 
of  Alderamin  is  28°  10'.  The  right  ascension  of 
the  former  is  338° ;  consequently,  it  is  22°  E.  of 

the  equinoctial  colure. 

\ 

TELESCOPIC    OBJECTS. 

x  CKPHEI.— A,  R.  =  20  h.  14  m.  08  s.  Dec.  =  -f-  77°  13'  06". 
A  fine  double  star  on  the  right  knee,  about  half-way  from  /3  Cephei  to  t 
Ursse  Minoris.  A  4^,  white,  B  8£,  blue,  The  colors  well  defined. 

Pos.  1260  12'         Dist   ()7".08         Epoch  1820.18     Striive. 
123    08  07  .50  1838.83     Smyth. 

There  is  little  evidence  of  any  change  in  the  position  of  the  components. 

/2  CKPHEI.— A.  R.  =  21  h.  26  m.  31  s.     Dec.  =  -f-  69°  51'  07". 
A  fine  double  star,  on  the  left  side  of  the  girdle.     A  3,  B  8,  magnitude. 
Pos.  251000'         Dist.   13".07         Epoch  1843.16     Smyth. 

CAMELOPARDUS. 

THE  CAMELOPARD. — This  constellation  was  made 
by  Hevelius  out  of  the  unformed  stars  which  lay 
scattered  between  Perseus,  Auriga,  the  heajfl  of  Ursa 
Major,  and  the  Pole  Star.  It  is  situated  directly 
N.  of  Auriga  and  the  head  of  the  Lynx,  and  occu- 
pies nearly  all  the  space  between  these  and  the 
pole.  It  contains  nearly  58  small  stars;  the  five 
largest  of  which  are  only' of  the  4th  magnitude. 
The  principal  star  lies  in  the  thigh,  and  is  about 
20°  from  Capella,  in  a  northerly  direction.  It  marks 
the  northern  boundary  of  the  temperate  zone;  being 
less  than  one  degree  S.  of  the  Arctic  circle.  There 
are  two  other  stars  of  the  4th  magnitude  near  the 


156  GEOGRAPHY  OF  THE  HEAVENS. 

right  knee,  12°  N.  E.  of  the  first  mentioned.  They 
may  be  known  by  their  standing  1°  apart  and 
alone. 

The  other  stars  in  this  constellation  are  too 
small,  and  too  much  scattered  to  invite  observation. 

TELESCOPIC     OBJECTS. 

A  BRIGHT   PLANETAE*    NEBULA. — A.  R.  =  03  h.  53  m.  29  s. 
Dec.  60°  23'  05".     On  the  flank  of  the  Camelopard.  See  map,  No.  VI. 
Discovered  by  Herschel,  1787. 

1  CAMELOPARBI. — A.  R.  =  04  h.  19  m.  23'.     Dec.  =  -\-  53°  33' 
03".     A  double  star  between  the  hind  hoofs.     A  7$,  "white,"  B  8£, 
*  blue."     See  map,  No.  VI. 

Pos.  307°  05'         Dist.  10".  13        Epoch  1830.57     StrLve. 

2  CAMELOPARDI.— A.  R.  =  04  h.  27  m.  18  s.     Dec.  53°  09'  00". 
A  close  double  star,  near  the  preceding  one,  and  between  the  hind  hools. 
A  5$,  yellow,  B  7£,  pale  blue.    See  map,  No.  VI. 

Discovered  by  Struve,  and  thus  measured  by  him  : 
Pos.  311040'         Dist.  1".585         Epoch  1829.79. 

A  DOUBLE  STAB.— A.  R.  =  04  h.  56  m.  19  s.  Dec.  =  -\-  79°  0 1 ' 
08".  Over  the  lower  part  of  the  back  of  the  Camelopard.  A  5£,  B  9, 
magnitude. 

Pos.  316°23/        Dist  37". 01         Epoch  1835.10     South. 
319    01  33  SO  1836.29     Smyth. 


CONSTELLATION  OF  SAGITTARIUS  157 

\ 

CHAPTER    IV. 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP  NO.    XVIII. 

SAGITTARIUS — THE  ARCHER. 

SCUTUM  SOBIESKI — THE  SHIELD  OF  SOBIESKI. 

Favorably  situated  for  examination  in  July,  August, 
and  September. 

SAGITTARIUS. 

THE  ARCHER. — This  is  the  ninth  sign  and  the 
tenth  constellation  of  the  Zodiac.  It  is  situated 
next  east  of  Scorpio,  with  a  mean  declination  of 
35°  S.  or  12°  below  the  ecliptic. 

The  sun  enters  this  sign  on  the  22d  of  Novem- 
ber, but  does  not  reach  the  constellation  before  the 
7th  of  December. 

It  occupies  a  considerable  space  in  the  southern 
hemisphere,  and  contains  a  number  of  subordinate, 
though  very  conspicuous  stars.  The  whole  num- 
ber of  its  visible  stars  is  sixty-nine,  including  five 
of  the  3d  magnitude,  and  ten  of  the  4th. 

It  may  be  readily  distinguished  by  means  of  five 
stars  of  the  3d  and  4th  magnitudes,  forming  a  figure 
resembling  a  little,  short,  straight-handled  Dipper, 
turned  nearly  bottom  upwards,  with  the  handle  to 
the  west,  familiarly  called  the  Milk-Dipper,  because 
it  is  partly  in  the  Milky- Way. 

This  little  figure  is  so  conspicuous  that  it  cannot 

easily  be  mistaken.     It  is  situated  about  33°  E.  of 

Antares,  and  comes  to  the  meridian  a  few  minutes 

after  Lyra,  on  the  17th  of  August.     Of  the  four 

0  .^ 


158  GEOGRAPHY  OF   THE   HEAVENS. 

stars  forming  the  bowl  of  the  Dipper,  the  two  up- 
per ones  are  only  3°  apart,  and  the  lower  ones  5°. 

The  two  smaller  stars  forming  the  handle,  and  extending  westwardly 
about  4£°,  and  the  easternmost  one  in  the  bowl  of  the  Dipper,  are  all 
of  the  4th  magnitude.  The  star  in  the  end  of  the  handle,  is  marked 
x,  and  is  placed  in  the  bow  of  Sagittarius,  just  within  the  Milky  Way. 
Lambda  may  otherwise  be  known  by  its  being  nearly  in  a  line  with  two 
other  stars  about  4^°  apart,  extending  towards  the  S.  E.  It  is  also 
equidistant  from  <p  and  J1,  with  which  it  makes  a  handsome  triangle,  with 
the  vertex  in  x.  About  5°  above  A,  and  a  little  to  the  west,  are  two 
stars  close  together,  in  the  end  of  the  bow,  the  brightest  of  which  is  of 
the  4th  magnitude,  and  marked  p..  This  star  serves  to  point  out  the 
winter  solstice,  being  about  2°  North  of  the  tropic  of  Capricorn,  and 
less  than  one  degree  east  of  the  solstitial  colure. 

If  a  line  be  drawn  from  <r  through  <}>,  and  produced  about  6°  farther 
to  the  west,  it  will  point  out  «T,  and  produced  about  3°  from  tT,  it  will 
point  out  y;  stars  of  the  3d  magnitude,  in  the  arrow.  The  latter  is  in 
the  point  of  the  arrow,  and  may  be  known  by  means  of  a  small  star 
just  above  it,  on  the  right.  This  star  is  so  nearly  on  the  same  meridian 
with  Etanin,  in  the  head  of  Draco,  that  it  culminates  only  two  minutes 
after  it. 

A  few  other  conspicuous  stars  in  this  constellation,  forming  a  variety 
of  geometrical  figures,  may  be  easily  traced  from  the  map. 


I  TELESCOPIC    OBJECTS. 

A  CLUSTER.— A.  R.  =  17  h.  55  m.  01  s.  Dec.  =  —  22°  30' 
Near  the  upper  part  of  the  bow  of  the  Archer.  It  is  a  coarse  cluster  of 
small  stars,  forming  a  circular  figure.  It  is  2£°  S.  E.  of  p.  Sagittani 
Discovered  by  Messier,  1764. 

p  SAGITTARII.— A.   R.  =  18  h.  04  m.  11  s.     Dec.  —  21°  05'  7". 
A  quadruple  star  on  the  north  end  of  the  Archer's  bow.     Registered  as 
triple  by  the  elder   Herschel.     Discovered  to  be  quadruple  by  his  son. 
A.  3£;  B.  16;  C.  9£;  D.  10,  magnitude. 
Pos.  A  B     =  260°  0  Dist.    10"0} 

AC     =315     0  40.  0  C  Estimations. 

A  D     =  114     5  45.03 

A  GLOBULAR  CLUSTER.— A.  R.  =  18  h.  14  m.  41  s.  Dec.  —24° 
56'  9".  Discovered  by  Messier,  1764.  Resolved  by  Sir  W.  Herschel. 
It  is  not  very  bright,  but  constitutes  a  good  test  for  space  penetrating 
power.  It  is  between  the  Head  and  Bow  of  the  Archer,  and  is  midway 
between  ft  Ophiuchi  and  ft  Lyras. 

A  LOOSE  CLUSTER.— A.  R.  =  18  h.  22  m.  14  s.  Dec.  —  19°  JO' 
2".  Between  the  Archer's  head  and  the  shield  of  Sobeiski.  "The 
gathering  portion  of  the  group  assumes  an  arched  form,  and  is  thickly 
strewn  in  the  upper  part  of  the  field,  where  a  pretty  knot  of  minute 


CONSTELLATION  OF  SAGITTARIUS.  159 

glimmerers  occupies  the  center,  with  much  star  dust  around."     It  is  5° 
N.  E.  of  p.  Sagittarii. 

A  GLOBULAR  CLUSTER. — A.  R.  =  18  h.  26  m.  25  s.  Dec.  —  24° 
01'  4".  In  the  space  between  the  head  and  bow  of  Sagittarius,  midway 
between  p  and  <r  Sagittarii.  Drawn  by  Le  Gentil  in  August,  1774. 
Described  by  Messier,  1764,  as  a  "  nebula  without  a  star."  Resolved  by 
Sir  W.  Herschel,  and  estimated  as  of  the  344th  order  of  distances. 

54  SAGITTARII.— A.  R.  =  19  h.  31  m.  33  s.  Dec.  — 16°  29'  2". 
A  delicate  triple  star  in  the  space  between  the  heads  of  Capricorn  and 
the  Archer,  A  5£;  B  8;  C  16;  magnitude. 

Discovered  by  Sir  John  Herschel 

Pos.  A  B     ==  420  8         Dist.  28'.5?  „    .         ,  1fto7  *Q 
A  C     =  280  0  20.0  5  Estimated  1837'58 

A  PALE  BLUE  PLANETARY  NEBULA.— A.  R.  =  19  h.  34  m.  56  s. 
Dec.  =  —  14°  31'  6".  Between  the  heads  of  Capricorn  and  Sagitta- 
rius. Discovered  by  Sir  W.  Herschel,  1787.  I  examined  this  object 
7th  July,  1847.  It  is  a  little  elongated,  very  sharply  illuminated,  and 
well  defined.  There  are  several  small  stars  in  the  field  of  view.  The 
bluish  tint  of  the  planetary  nebula  is  well  marked,  and  offers  another 
point  of  analogy  with'the  planets.  Herschel  and  Neptune  are  marked 
by  their  blue  tint,  and  indeed  1  am  confident  that  Neptune  was  seen  at 
th6  Cincinnati  Observatory  a  year  before  its  discovery.  It  was  thought 
to  be  a  planetary  nebula,  and  was  lost  from  the  field  of  view  by  accident 
before  its  position  was  taken.  But  the  region  of  space  was  well  remem- 
bered, and  the  moment  I  saw  the  planet  it  looked  familiar. 

A  GLOBULAR  CLUSTER. — A.  R.  =  19  h.  56  m.  38  s.  Dec.  =  — 
22°  22'  0".  Between  the  left  arm  of  Sagittarius  and  the  head  of  Cap- 
ricorn, 7^°.  S.  West  of  /3  Capricorni.  Discovered  by  Mechain,  1780. 
Resolved  by  Herschel,  and  located  by  him  in  the  734th  order  of  distan- 
ces. It  is  a  faint  cluster,  and  only  resolved  with  powerful  instruments. 


SCUTUM    SOBIESKI. 

SOBIESKI'S  SHIELD. — A  small  constellation  north  of 
the  Bow  and  Arrow  of  Sagittarius,  only  remarka- 
ble for  its  telescopic  objects. 

TELESCOPIC     OBJECTS. 

A  LARGE  NEBULA.— A.  R.  ='  18  h.  11  m.  23  s,  Dec.  =  —  16° 
15'  8".  Just  below  Sobieski's  Shield,  discovered  by  Messier,  1764,  and 
registered  as  a  train  of  light  without  stars.  Sir  W.  Herschel  describes 
the  object  as  follows :  "  A  wonderful  extensive  nebulosity  of  the  milky 
kind.  There  are  several  'stars  visible,  but  they  can  have  no  connection 


160        GEOGRAPHY  OF  THE  HEAVENS. 

with  the  nebulosity,  and  are  doubtless  belonging  to  our  own  system  and 
are  scattered  before  it."  His  son  says :  "  The  chief  peculiarities  which  I 
have  observed  in  it  are,  the  resolvable  knot  in  the  following  portion  of 
the  right  branch,  which  is  in  a  considerable  degree  isolated  from  the 
surrounding  nebula,  strongly  suggesting  the  idea  of  an  absorption  of 
the  nebulous  matter  ;  and  secondly,  the  much  smaller  and  feebler  knot 
at  the  north  preceding  end  of  the  same  branch,  where  the  nebula  makes 
a  sudden  bend  at  an  acute  angle."  I  have  examined  this  object  with 
great  attention,  and  do  not  find  its  appearance  as  figured  in  the  Bedford 
Catalogue.  We  are  not  informed  by  the  author,  whether  his  drawing  is 
original  or  copied.  The  horse  shoe,  or  Greek  Omega  ft  shape  given  to 
it  by  Capt.  Smyth,  disappears  under  the  12  inch  refractor. 

A  GREAT  CLUSTER A.  R.  =  18  h.  09  m.  49  s.     Dec.  =  18°  27'. 

Discovered  by  Messier,  1764,  a  rich  and  beautiful  object  in  a  dense 
portion  of  the  Milky  Way,  northeast  7°  from  p.  Sagittarii.  This  object, 
although  surrounded  by  a  vast  multitude  of  stars,  seems  to  be  separate 
and  distinct  from  them,  and  forming  a  universe  of  itself.  There  is  a 
large  star  near  the  center,  and  two  predominant  ones  in  the  north  pre- 
ceding edge  of  the  cluster.  This  cluster  strikes  with  more  astonishment, 
as  all  its  stars  are  distinct  and  comparatively  large.  It  is  well  shown 
by  a  telescope  of  moderate  power. 

A  FINE  FIELD  OF  STARS. — A.  R.  =  18  h.  08  m.  49  s.  Dec.  —  18° 
27'  05".  Below  the  left  base  of  the  Shield  of  Sobieski,  in  a  rich  portion 
of  the  Milky  Way. 

Discovered  by  Messier,  1764;  and  described  by  him  as  "a  mass  of 
stars — a  great  nebulosity,  of  which  the  light  is  divided  into  several  parts." 
The  object  is  readily  resolved  with  powerful  instruments. 

A  TEt-Kscdpic  DOUBLE  STAR. — A.  R.  =  18  h.  07  m.  37  m.  Dec, 
—  _  190  55'  05".  A  8^;  B  10  ;  magnitude. 

Discovered  by  Sir  John  Herschel,  and  described  as  being  placed  in  u 
faint  nebula,  of  an  elliptical  form,  and  50"  in  diameter.  It  may  be  found 
1£°  northeast  of  ,u  Sagittarii. 

This  Constellation  was  formed  by  Hevelius,  and  lies  between  Antinoiis 
and  the  Serpent's  tail.  Having  no  very  bright  stars,  it  is  difficult  to 
trace.  A  line  drawn  from  %  in  the  knee  of  Antinoiis,  to  £"in  the  left 
knee  of  Ophiuchus,  passes  through  several  small  stars  in  the  Shield. 


CONSTELLATION  OF  HERCULES.  161 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATION  ON 

MAP    NO.  xix. 

HERCULES. 

Favorably  situated  for  examination  in  May,  June  and 
My. 

HERCULES. 

HERCULES  is  represented  on  the  map,  invested 
with  the  skin  of  the  Nemaean  Lion,  holding  a 
massy  club  in  his  right  hand,  and  the  three-headed 
dog  Cerberus  in  his  left. 

He  occupies  a  large  space  in  the  northern  hemis- 
phere, with  one  foot  resting  on  the  head  of  Draco, 
on  the  north,  and  his  head  nearly  touching  that  of 
Ophiuchus,  on  the  south.  This  constellation  extends 
from  12°  to  50°  north  declination,  and  its  mean  right 
ascension  is  255°;  Consequently  its  center  is  on  the 
meridian  about  the  21st  of  July. 

It  is  bounded  by  Draco  on  the  north,  Lyra 
on  the  east,  Ophiuchus  or  the  Serpent- Bearer  on 
the  south,  and  the  Serpent  and  the  Crown  on  the 
west. 

It  contains  one  hundred  and  thirteen  stars,  inclu- 
ding one  of  the  2d,  or  of  between  the  2d  and  3d 
magnitudes,  nine  of  the  3d  magnitude,  and  nine- 
teen of  the  4th.  The  principal  star  is  Efts  Algethi, 
marked  a,  is  situated  in  the  head,  about  25°  south- 
east of  Corona  Borealis.  It  may  be  readily  known 
by  means  of  another  bright  star  of  equal  magni- 
tude, 5°  east,  or  southeast  of  it,  called  Ras  Alhague. 
Ras  Alhague  marks  the  head  of  Ophiuchus,  and 
Ras  Algethi  that  of  Hercules.  These  two  stars 
are  always  seen  together,  like  the  bright  pairs  in 
Aries,  Gemini,  the  Little  Dog,  &c.  They  come  to 
our.  meridian  about  the  28th  of  July,  near  where 
o2 


162  GEOGRAPHY   OF   THE   HEAVENS. 

Jit 

the  sun  does,  the  last  of  April,  or  the  middle  of 
August. 

About  midway  between  Ras  Algethi  on  tbe  southeast, >and  the  Northern 
Crown  on  the  northwest,  may  be  seen  yg  and  y.  two  stars  of  the  3d 
magnitude,  situated  in  the  west  shoulder,  about  3°  apart  The  north- 
ernmost of  these  two  are  called  Rutiltcuft. 

Those  four  stars  in  the  shape  of  a  diamond,  8°  or  10°  southwest  of 
the  two  in  the  shoulder  of  Hercules,  are  situated  in  the  head  of  the 
Serpent. 

About  12°  E.  N.  E.  of  Rutilicus,  and  10^°  directly  north  of  Ras 
Algethi,  are  two  stars  of  the  4th  magnitude,  in  the  east  shoulder.  They 
may  be  known  by  two  very  minute  stars  a  little  above  them  on  the  left 
The  two  stars  in  each  shoulder  of  Hercules,  with  Ras  Algathi  in  the 
head,  form  a  regular  triangle. 

The  left,  or  east  arm  of  Hercules,  which  grasps  the  triple-headed 
monster  Cerberus,  may  be  traced  by  means  of  three  or  four  stars  of  the 
4th  magnitude;  situated  in  a  row  3°  and  4°  apart,  extending  from  the 
shoulder,  in  a  northeasterly  direction.  Thai  small  cluster,  situated  in  a 
triangular  form,  about  14°  northeast  of  Ras  Algethi,  and  13°  east- 
southoast,  of  the  left  shoulder,  distinguish  the  head  of  Cerberus. 

Eighteen  or  20°  northeast  of  the  Crown,  are  four  stars  of  the  3d  and 
4th  magnitudes,  marked  TT,  »,  £>  «>  forming  an  irregular  square,  of  which 
the  two  southern  ones  are  about  4°  apart,  and  in  a  line  6°  or  7°  south 
of  the  two  northern  ones,  which  are  nearly  7°  apart. 

Pi,  in  the  northeast  corner,  may  be  known  by  means  of  one  or  two 
other  small  stars,  close  by  it,  on  the  east.  E/a,  in  the  northwest  corner, 
may  be  known  by  its  being  in  a  row  with  two  smaller  stars,  extending 
towards  the  northwest,  and  about  4°  apart  The  stars  of  the  4th  mag- 
nitude, just  south  of  the  Dragon's  head,  point  out  the  left  foot  and  ancle 
of  Hercules.  ' 

Several  other  stars,  of  the  3d  and  4th  magnitudes,  may  be  traced  out 
in  this  constellation,  by  reference  to  the  map. 

TELKSCOPIC     OBJECTS. 

DOUBLE  AND  BINARY  STARS. — RAS  ALRT.THI  or  A  HERCULIS,  A.  R. 

=r  17  h.  07  m.  21  s.  Dec.  =  -f  14O  34'  05".  A  beautiful  double  star 
on  the  head  of  Hercules.  Dist.  =  4".5.  Pos.  11 8°  08'.  The  compo- 
nents are  of  the  magnitudes  3£  and  5£,  the  largest  star  orange,  the. 
smaller  one  greenish.  There  is  no  reason  to  believe" that  these  stars  are 
physically  united,  although  the  opinion  seems  to  have  prevailed  among 
astronomers  that  such  a  union  would  be  found  to  exist  among  all  the 
colored  double  stars. 

Pos.  117036'         Dist.  4".  92         Ep.  1847.62     Mitchel. 

y  HKRCTJLTS.— A.  R.  =  16  h.  14  m.  53  s.  Dec.  =-f  19O  32'  00". 
A  coarse  double  star  on  the  left  arm.  '  Dist.  38".7.  Pos.  242O  03'.  A 
3£  white,  B  10  lilac.  No  change  in  distance  or  position  has  been 
detected,  except  what  may  be  imputed  to  errors  of  observation.  •*•<•"' 


CONSTELLATION  OF  HERCULES.  163 

<f  HE K CULTS.— A.  R.  =  16  h.  35  m.  15  s.  Dec.  =  -|-  31°  53'  07". 
A  close  binary  star,  over  the  left  hip.  A  3d  magnitude,  B  6  magnitude. 

Discovered  by  Sir  W.  Herschel,  July,  1782. 

The  companion  was  subsequently  missed  by  the  discoverer,  as  he 
believed,  in  consequence  of  its  being  hid  by  the  larger  star.  He  makes 
th«  following  remark,  the  interest  of  which  is  greatly  enhanced  by  sub- 
sequent discoveries :  "  My  observations  of  this  star  furnish  us  with  a 
phenomenon  which  is  new  in  astronomy;  it  is  the  occuliatiun  of  (me  star 
by  another.  This  epoch,  whatever  be  the  cause  of  it,  will  be  equally 
remarkable,  whether  owing  to  solar  parallax,  proper  motion,  or  motion  in 
an  orbit,  whose  plane  is  nearly  coincident  with  the  visual  ray. 

The  star  was  seen  single,  up  to  1826,  when  a  few  measures  were  made 
by  Striive.  It  again  became  single  in  1828,  and  so  continued  up  to  183'2, 
since  which  time  its  double  character  has  been  followed.  In  1842  the 
distance  had  increased  to  I'M  77,  according  to  Miidler,  who  computed 
the  elements  of  the  orbit  of  this  swiftly  revolving  binary  system.  Its 
periodic  time  is  about  31  years.  On  the  evening  of  the  15th  of  Sept., 
1847,  the  following  measures  were  made  with  the  Cincinnati  Refractor. 

Pos.  1090  12'        Dist.  1".078 

»  HERCULIS.— A.  R.  =  16  h.  37  m.  25  s.  Dec.  =-j-  39O  13'  08", 
an  exceedingly  close  double  star,  on  the  left  thigh. 

Discovered  by  Striive,  1827,  and  ranked  among  his  closest  objects. 

It  became  single,  and  few  if  any  reliable  measures  have  since  been 
obtained.  It  has  been  many  times  attentively  examined  by  myself,  and 
especially  on  the  evening  of  the  27th  July,  1847,  when  a  power  of  1200 
was  employed.  My  assistant  and  myself  agreed  that  the  star  was  slightly 
elongated  nearly  along  the  parallel,  but  it  was  very  uncertain. 

«T  HBHCITLIS.— A.  R.  =17  h.  08  m.  28  s.  Dec.  -f-  25C  01'  09".  A 
presumed  binary  star,  on  the  right  shoulder.  A  4.  B  8£  magnitude, 
on  the  following  evidence  : 

Pos.  =  162°  28'  Dis.  33"  75  Ep.  1779.61     Herschel. 

«          173    42  •'     26  .11  "    1829.77     Struve. 

«         175    01  "     24  .05  •<    1839.62     Smylh. 

Other  double  stars  will  be  found  by  an  examination  of  the  star  map. 
Among  them  x.  on  the  left  elbow,  p  on  the  right  thigh,  A.  on  the  right 
arm,  and  p  in  the  bend  of  the  left  arm,  are  the  brightest. 

GREAT  CLUSTER.— A.R.=15  h.  35  m.  58  s.  Dec.  =  -f-  36°  45'  08". 
3^°  from  »  Herculis,  and  on  the  line  joining  »  with  ^. 

This  object  was  discovered  by  Halley  in  1714,  and  was  described  as 
a  "  little  patch  of  light." 

It  was  reexamined  by  Messier  in  1764,  but  its  true  character  was  still 
unrevealed.  Messier  was  uncertain  whether  any  ctar  was  within  the 
nebula.  Under  the  power  of  Sir  William  Herschel's  great  reflector, 
this  object,  so  faintly  seen  by  Messier,  burst  into  ten  thousand  stvirs.  It 
is  certainly  one  of  the  most  magnificent  objects  in  the  heavens,  ami  is 
scarcely  ever  seen  for  the  first  time  without  exclamations  of  astonish- 
ment. The  drawing  will  be  found  to  agree  with  the  following  descrip- 


164  GEOGRAPHY  OF  THE   HEA\ENS. 

tion,  written  while  the  object  was  under  the  eye,  on  the  evening  ot  13th 
July,  1847,  in  the  Cincinnati  Observatory. 

"  A  brilliant  cluster,  nearly  globular.  A  spur  of  bright  stars  runs  off 
to  the  left,  terminating  in  a  sharp  point.  Then  follows  iu  going  round 
the  center,  from  north  to  east,  a  dark  space ;  at  90°  from  the  first  spur  or 
ray,  another  is  seen  less  perfectly  formed,  and  more  broken  at  the 
extremity,  containing  a  pair  of  double  stars  near  the  end.  The  next 
90°  pretty  well  filled  with  stars  out  to  the  circumference,  passing  through 
the  extremities  of  the  radiations  of  stars.  Then  another  imperfectly 
formed  spur  of  stars,  containing  a  pair  of  double  stars  midway  between 
the  center  and  the  extremity  of  the  spur.  The  space  next  following 
rather  vacant,  especially  near  the  double  star  ;  then  follows  a  bent  radia- 
tion of  bright  stars  curving  to  the  right,  and  causing  the  upper  part  of 
the  cluster  to  assume  a  flattened  figure." 

This  is  doubtless  one  of  the  many  magnificent  '•  ishmd  universes,'' 
recently  revealed  by  the  great  instruments,  of  modern  times.  In  1716 
it  constituted  one  of  six  known  nebula.  '  In  1766,  the  number  had 
increased  to  103,  and  is  now  above  3,000 !  The  clustering  of  suns  at 
the  center  of  this  grand  astral  system,  is  greater  than  is  fairly  attributable 
to  the  optical  effect  in  piercing  by  the  visual  ray  through  a  globular 
cluster  of  equally  distributed  stars.  There  seems  to  bt-  a  condensing 
power,  which  has  exerted  itself  to  draw  the  central  suns  into  closer 
proximity. 

A  GLOBULAR  CLUSTER. — A.  R.  17  h.  12  m.  14s.  Dec.  =  -[- 
43°  18'.  01£°  northeast  of  »  Herculis. 

Discovered  by  Messier  in  1781,  and  seen  by  him  as  a  nebula  without 
stars. 

With  fine  instruments  it  proves  to  be  a  brilliant  object,  some  7'  or  8' 
in  diameter,  surrounded  with  many  straggling  stars.  A  group  of  brighter 
stars  forms  an  inverted  figure  six  around  and  above  the  nucleus  of  the 
cluster.  It  is  of  the  same  character  as  the  preceding  object,  but  is  less 
extensive,  and  probably  much  more  remote.  Both  these  clusters  may 
be  resolved  with  a  4  inch  glass,  and  a  power  of  100  to  200  times.  They 
form  fine  objects  for  examination. 

A  FINE  PLANETARY  NEBULA.— A.  R.  =  16  h.  42m.  23s.  Dec. 
=  _|_  470  49'.  40  east  by  north  from  T  Hercuhs. 

Discovered  in  May,  1787. 

It  is  a  large,  round,  pale  blue  nebula,  and  has  been  mistaken  for  a 
comet.  The  size  of  these  objects,  in  case  we  regard  them  as  remote  as 
the  fixed  stars,  must  be  vast  beyond  comprehension.  If  an  object  having 
a  diameter  of  95  millions  of  miles,  can  only  be  seen  as  a  mere  point  of 
light,  what  must  be  the  actual  dimensions  of  these  planetary  nebulae, 
presenting  as  they  do,  in  many  instances,  measurable  diameters  of  fronr 
03"  to^O".  Such  stupendous  globes  favor  the  idea  that  these  are  vast 
collections  of  nebulous  matter,  slowly  condensing  under  the  power  of 
the  attraction  of  gravitation.  Such  objects  as  the  one  now  under  exam- 
ination, may  present  an  appearance  like  that  presented  by  our  own  .sun, 
when,  according  to  the  nebulous  theory,  its  expanded  dimensions 


CONSTELLATION  OF  HERCULES-  165 

embraced  the  grand  circumference  of  the  orbit  of  Neptune.  I  examined 
the  object  on  the  1st  of  August,  under  very  lavorabK'  circumstances. 
The  disk-like  character  which  usually  is  seen  on  planetary  nebula,  is 
not  well  defined  on  this  object.  Indeed  there  is  so  much  nebulous  haze 
surrounding  the  nucleus,  that  its  appearance  is  very  like  a  distant 
cluster.  The  haze  fades  away  by  degrees  from  the  nucleus,  and  is  finally 
lost. 

There  are  three  7th  magnitude  stars  in  the  field  of  view.  The  nebula 
is  some  7"  or  8"  in  diameter. 

A  SMALL  PLANETARY  NKBTJLA. — A.R.  =  16  h.  37  m.  46  s.  Doe. 
:=  -}-  24°  05'.  This  object  is  bright  and  well  defined.  I  examim-d  it 
closely  on  the  1st  of  August,  1847.  Its  disk  is  about  8"  in  diameter, 
and  a  little  elongated  in  one  direction. 

Discovered  by  Striive. 


DIRECTIONS   FOR  TRACING   THE  CONSTELLATIONS  ON 

MAP     NO.    XX. 

CYGNUS — THE  SWAN. 
LYRA — THE  HARP. 
LACERTA — THE  LIZARD. 

Favorably  situated  for  examination  in  August,  Sep- 
tember and  October. 

CYGNUS. 

THE  SWAN. — This  remarkable  constellation  is 
situated  in  the  Milky  Way,  directly  east  of  Lyra, 
and  nearly  on  the  same  meridian  with  the  Dolphin. 
It  is  represented  on  outspread  wings,  flying  down 
the  Milky  Way,  towards  the  southwest. 

The  principal  stars  which  mark  the  wings,  the 
body  and  the  bill  of  Cygnus,  are  so  arranged,  as  to 
form  a  large  and  regular  Cross;  the  upright  piece 
lying  along  the  Milky  Way  from  northeast  to  south- 
west, while  the  cross  piece,  representing  the  wings, 
crosses  the  other  at  right  angles,  from  southeast  to 
northwest. 


166  GEOGRAPHY  OF   THE   HEAVENS. 

Arided,  or  Deneb  Cygni,  marked  a,  in  the  body 
of  the  Swan,  is  a  star  of  the  2d  magnitude,  24° 
east-northeast  of  Lyra,  and  30°  directly  north  of 
the  Dolphin.  It  is  the  most  brilliant  star  in  the 
constellation,  and  is  situated  at  the  upper  end  of 
the  cross,  and  comes  to  the  meridian  at  9  o'clock, 
on  the  16th  of  September. 

Sad'r,  marked  y,  is  a  star  of  the  3d  magnitude,  6°  southwest  of 
Deneb,  situated  exactly  in  the  cross,  or  where  the  upright  piece  inter- 
sects the  cross  piece,  and  is  about  20°  east  of  Lyra. 

Delta,  the  principal  star  in  the  west  wing,  or  arm  of  the  cross,  is 
situated  northwest  of  Sad'r,  at  the  distance  of  little  more  than  8°,  and 
is  of  the  4th  magnitude.  Beyond  <T  towards  the  extremity  of  the  wing 
are  two  smaller  stars  about  5°  apart,  and  inclining  a  little  obliquely  to 
the  north ;  the  last  of  which  reaches  nearly  to  the  first  coil  of  Draco. 
These  stars  mark  the  west  wing ;  the  east  wing  may  be  traced  by  means 
of  stars  very  similarly  situated. 

Gienah,  marked  t,  is  a  star  of  the  4th  magnitude,  in  the  east  wing, 
just  as  far  east  of  Sad'r  in  the  center  of  the  cross,  as  (f  is  west  of  it. 
This  row  of  three  equal  stars,  <T,  y,  and  s,  form  the  bar  of  the  cross,  and 
are  equidistant  from  each  other,  being  about  8°  apart.  Beyond  s  on  the 
east,  at  the  distance  of  6°  or  7°  there  are  two  other  stars,  one  of  the  3d, 
the  other  of  the  4th  magnitude ;  the  last  of  which  marks  the  extremity  of 
the  eastern  wing. 

The  stars  in  the  neck  are  all  too  small  to  be  noticed.  There  is  one, 
however,  in  the  beak  of  the  Swan,  at  the  foot  of  the  cross,  called  Albireo, 
marked  @,  which  is  of  the  3d  magnitude,  and  can  be  seen  very  plainly. 
It  is  about  16°  southwest  of  Sad'r,  and  about  the  same  distance  south- 
east of  Lyra,  with  which  it  makes  nearly  a  right  angle. 

"  In  the  small  space  between  Sad'r  and  Albireo,"  says  Dr.  Herschel, 
'•  the  stars  in  the  Milky  Way  seem  to  be  clustering  into  two  separate 
divisions ;  each  division  containing  more  than  one  hundred  and  sixty- 
Jive  thousand  stars." 

Albireo  bears  northerly  from  Altair  about  20°.  Immediately  south 
and  southeast  of  Albireo,  may  be  seen  the  Fox  and  Goose  :  and  about 
midway  between  Albireo  and  Altair,  there  may  be  traced  a  line  of  four 
or  five  minute  stars,  called  the  ARROW  ;  the  head  of  which  is  on  the 
southwest,  and  can  be  distinguished  by  means  of  two  stars  situated  close 
together. 

According  to  the  British  catalogue,  this  constellation  contains  eighty- 
one  stars,  including  one  of  the  1st  and  2d  magnitude,  six  of  the  3d,  and 
12  of  the  4th. 

TELESCOPIC     OBJECTS. 

0  CYGXI  —A.  R.  =  19  h.  24  m.  16  s.  Dec.  -j-  27°  37'  07".  A 
large  and  brilliant  colored  double  star  on  the  bill  of  the  Swan,  13^° 
southeast  of  Vega,  or  a.  Lyra?.  A  3,  B  7,  magnitude.  The  principal 


CONSTELLATION    OF    CVGNUS.  167 

star  is  orange,  while  the  companion  is  a  blue,  presenting  a  fine  contract 
in  color.  Bradley  measured  the  components  in  1755,  since  which  no 
sensible  change  has  occurred. 

Pos.  57°  34'         Dis.  34".20         Epoch  1755.00 

The  best  position  is  54°  40",  as  about  a  mean  between  those  of 
Herschel,  Piazzi,  Striive,  South,  Dawes,  and  Smyth,  none  of  whom 
differ  from  the  others  in  their  results  by  a  whole  degree.  This  star 
forms  one  of  a  group  of  five  in  the  shape  of  a  cross,  and  point  out  the 
body  of  the  Swan.  They  may  readily  be  found  on  the  map  ;  ^  is  at 
the  extremity  of  the  longer  part  of  the  principal  piece  in  the  cross. 

<f  CYGNI.—  A.  R.  =  19  h.  39  m.  58.  Dec.  -j-  44O  44'  06".  A 
delicate  double  star  in  the  middle  of  the  left  wing  of  the  .Swan,  preceding 
a.  Cygni  by  13°,  and  on  the  same  parallel.  A  3£,  pale  yellow,  B  9, 
sea-green.  •% 

Discovered  by  Herschel,  who  made  these  measures. 

Pos.  71°  39'         Dist.  2".50         Epoch  1783.82. 

This  star  has  occasioned  no  little  difficulty,  in  consequence  of  the  dis- 
appea  ranee  of  the  small  companion  during  the  years  from  1802  up  to 
1823.  Since  that  time  it  has  been  regularly  followed.  Herschel's 
distance  seems  to  have  been  in  error,  as  the  following  measures 
will  show  : 

Pos.  40039'         Dis.  1  ".9  1         Epoch  1826.55     Striive, 
'«     36    42  »     1  .57  v  "       1831.73         « 

«     31    53  "     I  .80  "       1836.52         « 

Midler  thinks  the  stars  may  perform  a  revolution  about  their  common 
center  of  gravity  in  about  575  years  of  our  time. 


.—  A.  R.=  I9h.  40m.21s.«  Dec.  -f-  33°  21'  07".  A  fine 
double  star  on  the  Swan's  neck,  7^°  distant  from  @,  in  a  north-north- 
east direction.  A  5  mag.,  B.  9,  pale  blue. 

Discovered  by*Herschel,  in  1781. 

Since  good  measures  have  been  obtained,  no  reliable  change  in  dis- 
tance or  position  has  been  perceived. 

Pos.  720  38'  05"         Dis.  26".821         Epoch  1841.49     Madler. 


4  CrrrXT.—  A.  R.  =  19  h.  51  m.  30  s.  Dec.  -f-  52O  01'.  A  double 
star,  between  thertipof  the  Swan's  preceding  wing  and  the  tail.  A  5£, 
bright  white,  B  8,  lilac. 

Pos.   1840  02'         Dis.  3"  .05         Epoch   1837.53     Smyth. 

No  change  has  been  perceived  in  this  beautiful  set  of  stars. 

K  CTGNI.—  A.  R.  =  20  h.  41  m.  1  1  s.  Dec.  -f-  35O  54'  03",  a  close, 
double  star,  on  the  Swan's  lower  or  right  wing,  5°  south-east  of  y  Cyg- 
ni. A  5,  B  6  mag. 

Pos.  130000'         Dis.  0".07         Epoch  1843.71     Struve. 

61  CYGNI.—  A.  R.  =  20  h.  59  m.  43  s.  Dec.  -f-  37O  58'.  A  bina- 
ry star,  on  the  inner  tip  of  the  Swan's  right  wing.  A  5£,  B  5  magni- 
tude, both  yellow.  This  system  clusters  round  it  more  of  interest  than 
any  other  in  the  heavens.  Its  binary  character,  the  swiftness  of  its 


1G8        GEOGRAPHY  OF  THE  HEAVENS. 

proper  motion,  the  determination  of  its  annual  parallax  and  distance,  the 
computation  of  its  mass,  and  its  influence  on  Miidler's  wonderful  theory 
of  the  Central  Sun,  all  combine  to  make  it  an  object  of  great  impor- 
tance. Piazzi  was  the  first  to  announce  the  rapid  and  equable  proper 
motion  of  the  components  of  this  system,  amounting  to  5".02,  in  A.  R. 
and  3".02  in  declination.  With  such  a  proper  motion,  and  the  approxi- 
mate distance  first  obtained  by  MM.  Arago  and  Mathieu.  it  is  easily  de- 
monstrated that  these  two  suns  are  sweeping  through  space  with  such  an 
amazing  velocity  that  it  exceeds  the  swiftness  of  Mercury  60,000  times. 
Even  this  astounding  result  was  subsequently  found  to  fall  far  below  the 
truth.  After  mounting  the  great  Heliometer  of  the  Koningsburgh  Obser- 
vatory, M.  Bessel  determined  to  examine  this  double  star,  with  a  view  to 
the  exact  determination  of  its  annual  parallax.  After  a  long  series  of 
elaborate  and  delicate  observations,  his  efforts  were  crowned  with  success, 
and  in  1838  he  writes  to  Sir  John  F.  W.  Herschel,  as  follows: 

"I  selected  among  the  stars  which  surround  61  Cygni,  two  between 
the  9th  and  10th  magnitudes,  of  which  one  («)  is  nearly  perpendicular 
to  the  line  joining  the  two  stars,  and  the  other  nearly  in  the  direction 
of  this  line.  I  have  measured  the  distances  of  these  stars  from  the 
point  which  bisects  the  same  distance  between  the  two  stars  of  61 
Cygni.  I  have  commonly  repeated  the  observation  sixteen  times  every 
night."  • 

From  these  observations,  it  was  discovered  that  the  centrr!  point  be- 
tween the  components  of  61  did  not  remain  at  the  same  distance  from 
the  stars  of  reference,  but  was  more  than  0".6  further  from  the  star  (a) 
in  summer  than  in  winter.  After  proper  reduction,  the  parallax  was 
found  to  be  0".3136,  with  reference  to  which  we  record  Bessel's  remarks, 
in  the  following  language : 

"As  the  mean  error  of  the  annual  parallax  of  61  Cygni  is  only  rfc 
0".0202,  and  consequently  not  one-fifteenth  of  its  computed  value,  and 
as  these  comparisons  show  that  the  progress  of  the  influence  of  the  par- 
allax, which  the  observations  indicates,  follows  the  theory  as  nearly  as 
can  be  expected,  considering  its  smallness,  we  can  no  longer  doubt 
that  this  parallax  is  sensible.  Assuming  it  0"  3136,  we  find  the  distance 
of  the  star  61  Cygni  from  the  sun  657,700  times  the  mean  distance  of 
the  earth  from  the  sun.  Light  employs  1 0.3  years  to  traverse  the  dis- 
tance. As  the  annual  proper  motion  of  61  Cygni  amounts  to  5".  123 
of  a  great  circle,  the  relative  motion  of  this  star  and  the  sun  must  be 
considerably  more  than  sixteen  semi-diameters  of  the  earth's  orbit,  and 
the  star  must  have  a  constant  of  aberration  of  more  than  52".  When  we 
shall  have  succeeded  in  determining  the  elements  of  the  motion  of  both 
the  stars  forming  the  double  star  round  their  common  center  of  gravity, 
we  shall  be  able  to  determine  the  sum  of  their  masses.  I  have  attentively 
considered  the  preceding  observations  of  the  relative  positions,  but  I  con- 
sider them  as  yet  very  inadequate  to  afford  the  elements  of  the  orbit. 
I  consider  them  only  sufficient  to  show  that  the  annual  angular  motion 
is  somewhere  about  two-thirds  of  one  degree ;  and  that  the  distance  at 
the  beginning  of  this  century  had  a  minimum  of  about  15".  We  are 
enabled,  hence,  to  conclude  that  the  time  of  a  revolution  is  more  than 
540  years,  and  that  the  semi-major  axis  of  the  orbit  is  seen  under  an 


CONSTELLATION   OF   CYGNUS.  )  69 

angle  of  more  than  1 5"  of  space.  If,  however,  we  proceed  from  these 
numbers,  which  are  merely  limits,  we  find  the  sum  of  the  masses  of 
both  stars  less  than  half  ihe  sun's  mass." 

These  extraordinary  details  had  already  rendered  this  star  of  extreme 
interest,  when  M.  Midler  published  to  the  world  his  great  theory  of  the 
Central  Sun,  and  refers  to  the  rapid  annual  proper  motion  of  61  Cygni, 
as  one  of  the  results  deducible  from  his  theory  ;  and  further  employs  its 
parallax  and  distance  in  estimating  the  distance  to  Alcyone,  in  the  Plei- 
ades, the  star  fixed  upon  as  the  present  center  of  our  Astral  system. 

Pos.     96003'         Dis.   16".3         Epoch  1839.69     Smyth. 
"      101    02  "     17  .3  "        1747.50     Mitchel. 

Other  double  and  multiple  stars  will  be  found  upon  the  charts. 

A  CURIOUS  NKHULA.— A.  R  =  19  h.  40  m.  35  a.  Dec.  -f-  50° 
07'  06".  It  is  thus  described  in  the  Bedford  catalogue : 

"  A  very  singular  object.  In  my  telescope  it  is  small,  and  somewhat 
resembles  a  star  out  of  focus  ;  but  both  the  Herschels  agree,  on  viewing 
it  through  their  powerful  instruments,  that  it  appears  to  constitute  a  con- 
necting link  between  the  planetary  nebulae  and  the  nebulous  stars.  It 
was  discovered  Sept-mber,  1793." 

I  have  repeatedly  examined  this  remarkable  object  with  a  12  inch  aper- 
ture. Its  diameter  is  about  5"  or  6",  and  when  the  gaze  is  attentively 
fixed  'upon  the  center,  the  nebulous  matter  gradually  fades  from  the 
sight,  and  a  clear,  bright,  round  star  is  seen  in  the  center.  This  star 
shows  no  radiations,  such  as  usually  accompany  stars  viewed  with  the 
full  opening,  but  has  a  clean  little  disk,  such  as  the  telescope  shows  on 
other  stars  with  a  reduced  aperture,  under  the  most  favorable  circum- 
stances. By  throwing  off'  the  eye  from  the  center,  and  looking  careless- 
ly over  the  field  of  view,  the  nebula  returns  in  all  its  beauty,  and  the 
central  star  is  no  longer  seen.  This  is,  doubtiess,  optical,  yet  it  is  not 
easily  explicable.  That  the  faint  nebula  should  be  better  seen  out  of  the 
aori-ft  of  vision,  is  easily  understood>  but  this  should  be  true,  also,  of  the 
central  s,tar,  and  when  the  nebula  brightens  up  under  the  eye,  the  star 
should  increase  in  brilliancy  in  the  like  proportion. 

In  case  we  abandon  the  nebular  hypothesis,  this  object,  and  one  or  two 
others  of  like  character,  become  utterly  inexplicable.  If  we  say  that  each 
particle  of  nebulous  light  is  a  sun  or  star,  and  that  the  mass  of  hazy  light, 
so  uniform  in  its  brightness,  is  but  the  clustering  of  millions  of  suns  in 
a  flat  annulus.  how  stupendous  must  be  the  size  of  that  lucid  point 
which  occupies  the  center  of  this  wonderful  object,  and  is  so  distinctly 
revealed  by  the  telescope  1  The  old  idea  of  a  mighty  predominant  cen- 
tral globe  would,  on  such  an  hypothesis,  seem  to  be  well  founded,  for  it 
would  require  millions  of  nebulous  points  to  constitute  a  blaze  of  light 
equal  to  this  central  star.  This  object  is  found  on  the  tip  of  the  pre- 
ceding wing  of  the  Swan,  and  5£°  north  of  eT  Cygni. 

A  LOOSE  SMALL  CLUSTER — A.  R.  =  20  h.  18  m.  17  s.  Dec,  -}- 
370  59'  09". 

Discovered  by  Messier,  1764. 

Near  the  root  of  the  Swan's  neck  I  counted  but  twenty  stars  in  the 
field  oi  view,  July,  1847,  and  these  were  much  scattered. 
P 


J70        GEOGRAPHY  OF  THE  HEAVENS. 

A  SMALL  CLUSTER,  on  RICH  FIELD. — A.  R.  =  21  h.  26  m.  29  s. 
Dec.  -\-  47°  43'  08".  It  is  between  the  Swan's  tail  and  the  Lizard. 

Many  other  clusters  and  nebulae  will  be  found  on  the  chart,  from 
which  their  places  in  the  heavens  may  be  readily  found. 


LYRA. 

THE  HARP. — This  constellation  is  distinguished  by 
one  of  the  most  brilliant  stars  in  the  northern  hem- 
isphere. It  is  situated  directly  south  of  the  first 
coil  of  Draco,  between  the  Swan,  on  the  east,  and 
Hercules,  on  the  west ;  and,  when  on  the  meridian, 
is  almost  directly  overhead. 

It  contains  twenty-one  stars,  including  one  of 
the  1st  magnitude,  two  of  the  3d,  and  as  many  of 
the  4th. 

"  There  Lyra,  for  the  brightness  of  her  stars, 
More  than  their  number,  eminent ;  thrice  seven 
She  counts,  and  one  of  these  illuminates 
The  heavens  far  round,  blazing  imperial, 
In  the  first  order." 

This  star,  of  "  the  first  order,  blazing  with  impe- 
rial "  luster,  is  called  Vega,  marked  a,  and  sometimes 
Wega  ;  but  more  frequently  it  is  called  Lyra,  after 
the  name  of  the  constellation. 

There  is  no  possibility  of  mistaking  this  star  for 
any  other.  It  is  situated  14f°  S.  E.  of  7  Draconis. 
It  may  be  certainly  known  by  means  of  two 
small,  yet  conspicuous  stars,  of  the  5th  and  6th 
magnitude,  situated  about  2°  apart,  on  the  east  of 
it,  and  making  with  it  a  beautiful  little  triangle, 
with  the  angular  point  at  Lyra. 

The  northernmost  of  these  two  small  stars  is  marked  «,  and  the  south- 
ern one,  £.  About  2°  S.  E.  of  £",  and  in  a  line  with  Lyra,  is  a  star  of 
the  4th  magnitude,  marked  <?.  in  the  middle  of  the  Harp;  and  4°  or  5° 
S.  of  <T.  are  two  stars  of  the  3d  magnitude,  about  2°  apart,  in  the  garland 
of  the  Harp,  forming  another  triangle,  whose  vertex  is  in  ef.  The  star 


CONSTELLATION   OF   LYRA.  171 

on  the  east  is  marked  y  ;  that  on  the  west,  /3.  If  a  line  be  drawn  from 
y  Draconis  through  Lyra,  and  produced  6°  farther,  it  will  reach  /3.  . 

This  is  a  variable  star,  changing  from  the  3d  to  nearly  the  5th  magni- 
tude in  the  space  of  a  week.  It  is  supposed  to  have  spots  on  its  surface 
and  to  turn  on  its  axis,  like  our  sun. 

Gamma  comes  to  the  meridian  21  minutes  after  Lyra,  and  precisely 
at  the  same  moment  with  «,  in  the  tail  of  the  Eagle,  17£°  S.  of  it. 


The  declination  of  Lyra  is  about  38§°  N.;  conse- 
quently, when  on  the  meridian,  it  is  but  2°  S.  of  the 
zenith  of  Hartford.  It  culminates  at  9  o'clock, 
about  the  13th  of  August.  It  is  as  favorably  situ 
ated  to  an  observatory  at  Washington,  as  Rastabeu 
is  to  those  in  the  vicinity  of  London. 

Its  surpassing  brightness  has  attracted  the  at- 
tention of  astronomers  in  all  ages.  Manlius, 
who  wrote  in  the  age  of  Augustus,  thus  alludes 
to  it: 

"  OXF.,  placed  in  front  above  the  rest,  displays 
A  vigorous  light,  and  darts  surprising  rays." 

Astronomicon,  B.  i,  p.  15. 

TELESCOPIC    OBJECTS. 

VEGA,  OK  a  LYRA.— A.  R.  =  18  h.  31  m.  30  s.  Dec.  =  -f-  38« 
38'  01",  the  most  brilliant  star  in  the  northern  hemisphere,  attended  by  a 
companion  of  the  llth  magnitude,  distant  43". 

Pos.  140°         Epoch   1843 

There  is  no  reason  to  believe  that  the  relation  between  these  two  stars 
is  other  than  optical.  The  proper  motion  of  Vega  occasions  a  change  in 
the  distance  and  angle  of  position  of  the  small  companion.  Many  ef- 
forts have  been  made  to  obtain  the  annual  parallax  of  this  star.  In 
18-*6,  M.  Striive  concluded  the  value  of  the  parallax  to  be  0".12o,  with 
a  probable  error  of  0".055.  This  result  yields  a  distance  of  one  and  a 
half  millions  of  times  the  semidiameter  of  the  earth's  orbit.  The  ap- 
pearance of  A  Lyrae  in  large  telescopes  is  truly  magnificent.  Before  the 
star  enters  the  field  of  view,  its  coming  is  announced  by  a  dawn  of  light 
like  that  of  the  early  morning,  which  grows  brighter  and  brighter,  until 
the  star,  like  the  sun,  enters  the  field,  with  a  brilliancy  which  the  eye 
can  scarcely  bear.  By  artificial  occultation,  at  the  Cincinnati  Observa- 
tory, no  less  than  sixteen  minute  stars  have  been  counted  within  the 
limits  of  this  dawn  surrounding  Vega. 

By  the  revolution  of  the  pole  of  the  equator  around  the  pole  of  the 
ecliptic,  in  about  10,000  years  this  brilliant  object  will  become  the  pule 
star. 


172  GEOGRAPHY  OF  THE  HEAVENS. 

The  stupendous  distance  of  Vega,  as  roughly  ascertained  by  Striive, 
gave  rise  to  his  ingenious  theory  as  to  the  prohahle  relative  positions  of 
the  stars  of  different  magnitudes.  He  considered  the  stars  of  the  first 
magnitude  distant  ahout  two  millions  of  times  the  radius  of  the  earth's 
orbit,  those  of  the  6th  magnitude  stxtten  millions,  those  of  the  12th 
sixty  millions  of  times  the  same  unit. 

ft  LYHK.— A.  R.  =  18°  44'  09".  Dec.  -{-  33°  10'  08",  a  coarse, 
quadruple  star.  Of  the  three  components,  A  is  of  the  3d,  B  of  the  8th, 
0  of  the  8^th,  and  D  of  the  9th  magnitude.  This  star  is  ranked  among 
the  variable  ones,  and  has  a  period  of  6  days,  10  hours,  35  minutes, 
changing  from  the  3d  to  the  5th  magnitude. 

i  ANII  5  LTRX.— A.  R.  =  18  h.  39  m.  02  s.  Dec.  =  -|-  39°  30' 
03",  a  double  star.  One  of  the  most  remarkable  objects  in  the  heavens, 
A  of  the  5th,  B  of  the  6£th  magnitude.  The  following  measures  show 
a  retrograde  motion. 

i  LYHJE.     A   B 

Pos.  330  55'         Dis.  3".44         Epoch  1779.83     Herschel. 
26     06  3  .03  1831.44     Striive. 

20     25  2  .46  1847.60     Mitchel. 

5  LTHJB.     O  D 

Pos.  1730  28'         DK  3".50         Epoch  1779.83     Herschel. 
155     10  2  .57  1831.44     Striive. 

149     10  2  .55  1847.60     Mitchel. 

There  is  strong  evidence  that  each  of  these  sets  is  binary.  A  revolv- 
ing about  B  in  about  2000  years,  while  0  and  D  complete  their  revolu- 
tion in  about  half  that  period. 

From  the  equality  of  proper  motions  in  the  four  stars,  it  is  inferred 
that  a  physical  union  may  exist  among  the  two  pairs,  in  which  case  the 
one  pair  will  perform  a  revolution  about  the  other  in  about  one  million 
of  years ! 

This  star  is  1£°  northeast  of  Lyrse,  and  may  be  readily  divided  into 
two  stars  with  the  smallest  optical  power.  The  quadruple  character  is 
made  out  with  a  power  of  150  or  200.  Several  minute  points  of  light 
are  seen  between  the  pairs. 

£  LYHJE.— A.  R.  =18  h.  39  m.  15  s.     Dec.  -{-  37°  26'  05",  a  coarse 
double  star.     A  5th,  B  5|th  magnitude. 
Pos.  249°  06'         Dis.  43".08 

v  LYRJS.— A.  R.  18  h.  43  m.  48s.  Dec.  -f  32°  38'  0",  a  coarse 
quadruple  star,  just  south  of  @,  easily  divided. 

v  LTRJ:.— A.  R.  19  h.  08  m.  18  s.     Dec.  =  -f-  28°  52'  05",  a  fine 
double  star ;  components  of  the  magnitudes  5  and  9. 
Pos.  84°  08'         Dis.  =28".3 

A  FINK  CLUSTER  OF  SMALL  STARS. — A.  R.  =  19  h.  10  m.  19s. 
Dec.  =  -f- 29°  54' 02". 


CONSTELLATION  OF  LYRA.  173 

Discovered  by  Messier,  1 778,  but  seen  by  him  as  a  faint  nebula. 

Resolved  by  Sir  William  Herschel  in  1784,  and  located  in  the  344th 
order  of  distances.  There  is  a  great  clustering  about  the  center,  and  a 
rich  profusion  of  stars  in  the  field  of  view.  It  may  be  found  on  a  line 
joining  /2  Lyrse  with  $  Cygni,  about  5£°  from  the  tirst  star.  This  object 
is  one  of  the  many  magnificent  astral  systems,  which  are  scattered  so 
profusely  through  the  boundless  regions  of  space.  Its  light  requires 
more  than  a  thousand  years  to  reach  our  system. 

THE  ANNULAR  NEBULA— A.  R.  =  18  h.  47  m.  37  s.  Dec.  =  -|- 
32°  50',  midway  between  @  and  y  on  the  cross-piece  of  the  Lyre. 

This  wonderful  object  was  first  noted  by  Darquier,  in  1779,  as  a  dim 
planetary  disk. 

On  examination  by  Sir  William  Herschel,  it  proved  to  be  in  the  form 
of  a  perforated  ring  or  annulus.  With  powerful  instruments  the  dark 
interior  is  seen  filled  with  faint  gauzy  light.  The  figure  is  not  exactly 
circular,  the  diameters  being  in  about  the  ratio  of  4  and  5.  Many 
persons  have  declared  their  conviction  that  they  saw  the  minute  stars 
which  it  is  believed  compose  this  singular  object.  I  have  never  been 
able  to  satisfy  myself  that  it  has  been  fairly  resolved.  Lord  Rosse's 
great  telescope  has  changed  its  figure  slightly,  by  finding  small  filaments 
of  light,  extending  within  and  without  the  ring,  in  the  direction  of  the 
larger  axis.  Herschel  estimates  the  profundity  of  this  object  to  be  of  the 
950th  order.  Such  an  amazing  distance  absolutely  overwhelms  the 
imagination.  A  thousand  times  the  distance  of  the  nearest  fixed  stars ; 
Its  magnitude  must  be  immense,  as  its  diameter  is  some  5"  or  6",  even 
when  seen  at  such  an  immeasurable  distance. 

It  requires  a  4  or  5  inch  refractor  to  yield  its  figure  distinctly  *o 
the  eye. 

It  is  visible  in  smaller  instruments,  but  would  be  mistaken  for  a  star, 
by  any  other  than  a  practiced  eye. 


174  GEOGRAPHY  OF  THE  HEAVENS. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.    XXI. 

AQUILA  ET  ANTINOUS — THE  EAGLE  AND  ANTINOUS. 
DELPHINUS — THE  DOLPHIN. 

TAURUS    PONIATOWSKI PONIATOWSKI'S    BULL. 

ANSER  ET  VULPECULA — THE  Fox  AND  GOOSE. 

Favorably  situated  for  examination  in  August,  Sep- 
tember, and  October. 

AQUILA  ET  ANTINOUS. 

THE  EAGLE  AND  ANTINOUS. — This  double  con- 
stellation is  situated  directly  south  of  the  Fox 
and  Goose,  and  between  Taurus  Poniatowski  on 
the  west,  and  the  Dolphin  on  the  east.  It  contains 
seventy-one  stars,  including  one  of  the  1st  magni- 
tude, nine  of  the  3d,  and  seven  of  the  4th.  It  may 
be  readily  distinguished  by  the  position  and  supe- 
rior brilliancy  of  its  principal  star. 

Altair,  marked  a,  the  principal  star  in  the  Eagle, 
is  of  the  1st,  or  between  the  1st  and  2d  magnitudes. 
It  is  situated  about  14°  southwest  of  Dolphin.  It 
may  be  known  by  its  being  the  largest  and  middle 
one  of  the  three  bright  stars  which  are  arranged 
in  a  line  bearing  northwest  and  southeast.  The 
stars  on  each  side  of  Altair  are  of  the  3d  magni- 
tude, and  distant  from  it  about  2°.  This  row  of 
stars  very  much  resembles  that  in  the  guards  of  the 
Lesser  Bear. 

Altair  is  one  of  the  stars  from  which  the  moon's 
distance  is  taken  for  computing  longitude  at  sea. 
Its  mean  declination  is  nearly  85°  north,  and  when 
on  the  meridian,  it  occupies  nearly  the  same  place 
in  the  heavens  that  the  sun  does  at  noon  on  the 
12th  day  of  April.  It  culminates  about  6  minutes 


CONSTELLATION  OF  AQUILA  ET  ANTINOUS.   175 

before  9  o'clock,  on  the  last  day  of  August.     It  rises 
acronycally  about  the  beginning  of  June. 

Ovid  alludes  to  the  rising  of  this  constellation  ;  or,  more  properly,  to 
that  of  the  principal  star,  Altair : — 

"  Now  view  the  skies, 

And  you'll  behold  Jove's  hook'd-bill  bird  arise." 

Massey's  Fasti. 

"  Among  thy  splendid  group 

ONE  dubious  whether  of  the  SECOND  HANK, 

Or  to  the  FIRST  entitled  ;  but  whose  claim 

Seems  to  deserve  the  FIRST."  Eudosia. 

The  northernmost  star  in  the  line,  next  above  Altair,  is  called 
Tarazed,  marked  y.  In  the  wing  of  the  Eagle,  there  is  another  row 
composed  of  three  stars,  situated  4°  or  5°  apart,  extending  down 
towards  the  southwest,  the  middle  one  in  this  line  is  the  smallest, 
being  only  of  the  4th  magnitude,  marked  /a ;  the  next  is  of  the  4th  mag- 
nitude, marked  Delia,  arid  situated  8°  southwest  of  Altair. 

As  you  proceed  from  /,  there  is  another  line  of  three  stars,  of  the  4th 
magnitude,  between  5°  and  fi°  apart,  extending  southerly,  but  curving  a 
little  to  the  west,  which  mark  the  youth  Antinous.  The  northern  wing 
of  the  Eagle  is  not  distinguished  by  any  conspicuous  stars. 

Zeta  of  the  3d  magnitude,  and  Epsilon  of  the  4th  magnitude,  are 
near  the  top  of  the  left  wing. 

From  f  to  6,  in  the  wrist  of  Antinous,  may  be  traced  a  long  line 
of  stars,  chiefly  of  the  3d  magnitude,  whose  letter  names  are  6,  »,  /u,  f, 
and  t.  The  direction  of  this  line  is  from  southeast  to  northwest,  and 
its  length  is  about  25°. 

Eta  is  remarkable  for  its  changeable  appearance.  Its  greatest  bright- 
ness conlinues  hut  40  hours;  it  then  gradually  diminishes  for  66  hours, 
when  its  luster  remains  stationary  for  30  hours.  It  then  waxes  brighter 
and  brighter,  until  it  appears  again  as  a  star  of  the  3d  magnitude. 

From  these  phenomena,  it  is  inferred  that  it  not  only  has  spots  on  its 
surface,  like  our  sun,  but  that  it  also  turns  on  its  axis. 

Similar  phenomena  are  observed  in  Algol,  @,  in  the  Hare,  <?,  in 
Cepheus,  and  o,  in  the  Whale,  and  many  others. 

"  Aquila  the  next, 

Divides  the  ether  with  her  ardent  wing; 
Beneath  the  Swan,  nor  far  from  Pegasus, 
POETIC  EAGLE." 

TELESCOPIC    OBJECTS. 

A  FIXE  CLUSTER.— A.  R.=18  h.  42m.  32.  Dec.  Q°  27'  02".  It 
precedes  the  left  foot  of  Antinous,  and  is  on  the  Shield  of  Sobieski. 

Discovered  by  Kirch  in  1681,  and  described  as  "a  small  obscure  spot 
with  a  star  shining  through." 

It  was  resolved  by  Dr.  Durham  in  1733.     This  was  one  of  the  six 


176        GEOGRAPHY  OF  THE  HEAVENS. 

clusters  or  nebulae  described  by  Halley  in  1716,  who  ventured  to  predict 
that  more  would  be  found.  This  object  is  figured-  in  the  Bedford  Cata- 
logue, but  is  very  different  from  that  presented  in  this  volume. 

A  TRIPLE  STAR.— A.  R.  =  18  h.  54  m.  31  s.  Dec.  —  0°  55' 
09".  Known  to  Piazzi  as  douMe,  subdivided  by  Striive.  A  9,  ti  9, C 
16,  magnitude. 

Pos.A  B   1480  0'        Dis.  25".6?  C  Smyth. 

B  C     85     0  2.0$    Epoch  1838.59    £  Esjmations> 

B  C     76     0  1  .576  1847.60        Mitchel. 

The  object  may  be  found  between  the  Eagle's  wing  and  the  left  heel 
of  Antinous. 

A  TRIPLE  STAR.— A.  R.  =19  h.  28  m.  01  s.      Dec.  =  —  10°  46' 
U8".     On  the  right  knee  of  Antinous.     A  9,  B  10,  C  12,  magnitudes. 
Pos.  A  B     338°  04'       Dis.  3".02     Epoch  1835.58     Smyth. 
A  C     153    05  8  .00  " 

A  B     319     04  2  .54  1847.60     Mitchel. 

169     17 

Some  suspicion  exists  with  reference  to  the  possible  binary  character 
of  the  set. 

A  DOUBLE  STAR.— A.  R.  —  18  h.  57  m.  59  s.  Dec.  -f-  6°  18'  08", 
on  the  edge  of  the  Eagle's  wing.  A  ?£,  B  9  magnitude. 

Pos.   154038'         Dis.  10".  1 33         Epoch  1831.70     Striive. 
•*       152    28  «       9  .492  «       1847.65     Mitchel. 

A  SMALL  AWU  LOOSE  CLUSTER. — A.  R.  19  h.  08  m.  36  s.  Dec.  — 
1°  IT  09",  between  the  lower  wing  of  the  Eagle  and  the  thigh  of  An- 
tinous, consisting  of  fifteen  or  twenty  stars,  with  indications  of  star-dust. 
Examined  16th  July,  1847. 

A  STELLAR  NEBULA. — A.  R.  =  19  h.  23  m.  55  s.  Dec.  -{-  8°  54' 
01",  on  the  Eagle's  back,  5°  east  of  Altair,  or  a.  Aquilae. 

Discovered  by  Sir  W.  Herschel,  and  estimated  at  the  900th  order  of 
distances.  Examined  on  the  16th  July,  1847. 

The  object  is  very  small,  brightening  at  a  vertex,  and  running  off  in 
the  shape  of  a  fan.  Several  stars  in  the  field ;  a  bright  one  above,  and 
one  below  the  nebula.  Sir  John  Herschel  says,  "  It  is  like  a  nebula  well 
resolved,  and  is  a  curious  object." 

A  DELICATE  DOUBLE  STAR.— A.  R.  =  19  h.  35  m.  02  s.  Dec.  = 
8°  00'  05",  on  the  Eagle's  back,  2°  east  of  Altair,  and  a  little  south  of 
the  parallel.  A  7£,  B  9^  magnitude. 

Pos.  2520  32'         Dis.  32".  12         Epoch  1825.52     Striive. 

v  AQ.UILK.— A.  R.  =  19  h.  41  m.  10  s.     Dec.  =  -f-  1 1<>  25'  04". 
A  close  double  star,  near  the  northern  wing  of  Aquilae.     A  6,  B  7  mag. 
Pos.    122°  00'         Dis.  1".50        Epoch  1831.70     Smyth. 
«       123    09  «      1   .20  «       1847.66     MitcheL 


CONSTELLATION  OF   AQUILA   ET   ANTINOUS.       177 

A  AHUIL*:.  —  A.  R.  =  19  h.  42  m.  58  s.  Dec.  =  -f-  8°  26'  09" 
A  first  magnitude  star,  with  a  10th  magnitude  companion,  suspected  to 
be  physically  united, 

Pos.  334044'         Dis.    143".40         Epoch   178156     Herschel. 
«     326    06  '•       153  .71  "      1821.85     Striive. 

»     323    06  «       152  .60  "      1834.81     Smith. 

The  change  may  be  due  to  a  difference  of  proper  motion  in  the  two 
stars.  The  annual  proper  motion  of  Altair  has  been  fixed  at  rather 
more  than  half  a  second  in  A.  R.,  and  about  one  third  of  a  second  in 
declination. 

23  AQ.UIL*.—  A.  R.  =  19  h.  10  m.  24  s.  Dec.  =  -j-  0°  48'  00". 
A  dose  double  star,  under  the  Eagle's  southern  wing. 

Discovered  by  Herschel,  who  appears  to  have  made  a  mistake  in  en- 
tering his  measures.  His  position  is  162°,  distance  3".oO,  epoch 
1781.58. 

The  Bedford  Catalogue  marks  the  position  more  than  180°  dif- 
ferent, arid  thinks  Herschel  wrote  south  for  north,  in  recording  his 
observations. 

This  star  was  carefully  measured  on  the  4th  of  August,  1847,  and 
gave  these  results: 

Pos.  12°  09'         Dis.  3".57. 

Bedford  Cat.  Pos.  =  12°  06'         Dis.  3".l         Epoch  1833.68. 


A  DOUBLE  STAK.—  A.  R.  =  19  h.  37  m.  21  s.     Dec.  -j-  10°  23'  06", 
on  the  Eagle's  head.     A  8,  B  10  magnitude. 

Pos.  2780  18'         Dis.  3".00         Epoch  1783.60     Herschel. 
276     27  3  .99  1825.56     South. 

276     30  4  .00  1836.76     Smyth. 

276     36  4  .33  1847.72     Mitchel. 

The  distance  between  the  components  seems  to  be  on  the  increase, 
while  the  angle  of  position  remains  nearly  if  not  quite  the  same. 


DELPHINUS. 

THE  DOLPHIN. — This  beautiful  little  cluster  of 
stars  is  situated  13°  or  14°  northeast  of  the  Eagle. 
It  consists  of  eighteen  stars,  including  two  of  the  3d 
magnitude,  and  three  of  the  4th,  but  none  larger. 
It  is  easily  distinguished  from  all  others,  by  means 
of  four  principal  stars  in  the  head,  which  are  so 
arranged  as  to  form  the  figure  of  a  diamond,  point- 
ing northeast  and  southwest.  To  many,  this  clus- 
ter is  known  by  the  name  of  Job's  Coffin;  but  from 
whom,  or  from  what  fancy,  it  first  obtained  this 
appellation,  is  not  known. 


178  GEOGRAPHY  OF   TEE  HEAVENS. 

There  is  a  star  of  the  4th  magnitude,  situated  in 
the  body  of  the  Dolphin,  about  3°  southwest  of  the 
Diamond,  and  marked  Epsilon.  The  other  four  are 
marked  A/p/ia,  Beta,  Gamma,  and  Delta.  Between 
these  are  several  smaller  stars,  too  small  to  be  seen 
in  presence  of  the  moon. 

The  mean  declination  of  the  Dolphin  is  about 
15°  north.  It  comes  to  the  meridian  the  same 
moment  with  Deneb  Cygni,  and  about  50  minutes 
after  Altair,  on  the  16th  of  September. 

"  Thee  I  behold,  majestic  Cygnus, 
On  the  marge  dancing  of  the  heavenly  sea, 
Arion's  friend  ;  eighteen  thy  stars  appear — 
One  telescopic." 

TELESCOPIC     OBJECTS. 

A  PLANETARY  NEBULA.— A.  R.  =  20  h.  15  m.  15  s.  Dec.  19° 
36'  06".  Between  the  Dolphin's  pectoral  fin  and  the  arrow's  head. 

Discovered  by  Sir  William  Herschei,  1782. 

This  is  a  large  though  faint  planetary  nebula,  the  surface  being  evenly 
illuminated,  ^ir  John  Herschei  suggests  that  the  minute  stars  in  close 
proximity  to  the  nebula,  may  be  satellites.  He  remarks  "  that  the 
enormous  magnitude  of  their  bodies,  and  consequent  probable  mass  (if 
they  be  not  hollow  shells) ;  may  give  them  a  gravitating  energy,  which, 
however  large  we  may  conceive  them  to  be1,  may  yet  be  capable  of  retain- 
ing in  orbits  three  or  four  times  their  own  diameter,  and  in  periods  of 
great  length,  small  bodies  of  stellar  character." 

Should  this  suggestion  ever  be  verified,  we  might  be  led  to  attribute 
eome  of  the  anomalous  motions  (as  yet  unaccounted  for),  among  some 
of  the  fixed  stars,  to  the  disturbing  influence  of  an  invisible  body  of  this 
character.  In  case  any  such  faint  body  were  situated  near  Sirius,  for 
example,  the  brilliancy  of  this  star  would  entirely  hide  the  nebula.  Arti- 
ficial occultation  may  detect  some  of  these  unknown  objects. 

A  SMALL  CLUSTER.— A.  R.  =  20  h.  26  m.  21  s.  Dec.  -f-  06° 
53',  near  the  Dolphin's  tail. 

Discovered  by  Sir  W.  Herschei,  1785. 

It  is  a  mass  of  small  stars,  with  several  larger  stars  in  the  field. 

$  DELPHIXI.— A.  R.  20  h.  30  m.  03  s.  Dec.  -\-  14°  02'  06".  A 
delicate  triple  star,  in  the  Dolphin's  body.  A  4,  B  1 2,  magnitude.  The 
minute  star  B,  was  added  to  the  previously  discovered  pair  by  Sir  John 
Herschei.  It  had  escaped  his  father  and  Striive. 

Pos.  A  B   1050  00'         Dis.  15".()         Epoch  1734.79 
A  C  341     08  30  .0  " 


CONSTELLATION  OF  DELPHINUS.        179 

y  DKLPHINI — A.  R.  20  h.  39  m.  15  s.  Dec.  -f-  15O  33'  02".  A 
beautiful  double  star  on  the  Dolphin's  head.  A  4,  yellow ;  B  7,  light 
green.  J\o  change  has  been  detected. 

Pos.  2730  03'  00"         Dis.  12".0        Epoch  1830. 


VULPECULA   ET  ANSER. 

THE  Fox  AND  THE  GOOSE. — This  is  a  modern  con- 
stellation, introduced  by  Hevelius,  into  a  space 
between  the  Arrow  and  the  Swan.  "  I  wished," 
remarked  Hevelius,  "  to  place  a  Fox  with  a  Goose 
in  this  space  of  sky  well  fitted  to  it,  because  such 
an  animal  is  very  cunning,  voracious,  and  fierce. 
Aquila  and  Vultur  are  of  the  same  nature,  rapa- 
cious and  greedy."  In  1672,  while  examining  this 
new  constellation,  Hevelius  discovered  a  star  in  the 
head  of  the  Fox,  which  he  had  never  before  seen. 
This  star  remained  visible  for  the  space  of  about 
two  years,  after  which  period  it  disappeared,  and 
has  never  since  been  recognized. 

This  nevv  constellation  has  been  pretty  fairly 
adopted  by  astronomers,  and  may  now  be  said  to 
be  pretty  firmly  fixed  in  the  heavens.  Its  author 
counted  27  stars  within  its  limits.  The  number 
has  been  successively  increased  by  later  astrono- 
mers, until  finally,  Bode  has  fixed  the  places  of  126 
stars  in  this  small  space.  *.!.»Sr* 

The  intrusions  or  additions  of  Hevelius  to  the 
old  constellations  have  been  better  received  by 
astronomers  than  those  of  any  other  modern  inno- 
vator, probably  because  his  constellations  were 
placed  where  they  seemed  to  be  actually  required 
for  convenience  of  reference. 

TELESCOPIC    OBJECTS. 

A  DELICATE  DOUBLE  STAR. — A.  R.  =  29  h.  00  m.  10  s.  De^ 
-j-  20°  38'  07".  Close  to  the  Arrow,  under  the  Fox's  shoulder.  A  8 
B  10,  magnitude. 

Discovered  by  Sir  James  South  in  1828. 

Pos.  340°  05         Dis.  5".5         Epoch  1839.70 


l&O  GEOGRAPHY  OF   THE  HEAVENS. 

A  SMALL  DOUBLE  STAR  —A.  R.  20  h.  15  m.  47  s.  Dec.  =  -f-  23° 
34'  02".  On  the  Fox's  loins.  A  8,  B  14,  indigo  blue. 

About  a  minute  of  time  preceding  this  object,  and  20'  south  of  it,  is 
a  minute  close  double  star,  discovered  by  Struve,  and  is  No.  2672  of  his 
great  catalogue. 

DUMB-BELL  NEBULA. — A.  R.  19  h.  52  m.  39  s.     Dec.  22°  17'  01". 

Discovered  by  Messier,  1764. 

This  is  one  of  the  large  and  magnificent  nebulae,  located  in  one  of 
the  richest  parts  of  the  heavens.  As  first  seen,  it  resembled  two  balls 
joined  together  like  a  dumb-bell,  or  double  headed  shot,  and  hence  its 
name.  As  more  powerful  instruments  have  been  directed  to  its  exam- 
ination, its  form  has  become  more  wonderful  and  mysterious.  The 
drawing  represents  this  object  as  seen  with  the  Cincinnati  Refractor, 
July,  1847,  at  which  time  it  was  described  while  under  the  eye,  as 
follows : 

"  The  shape  of  the  nebula  is  an  oval  or  ellipse,  whose  larger  axis 
occupies  four-fifths  of  the  field  of  view,  with  a  power  of  250.  The 
figure  imperfect  to  the  left  of  the  lower  vertex.  The  right  hand  ball  of 
light  rather  the  largest,  the  round  figure  being  broken  by  two  blunt 
points.  7'he  upper  star  is  seen  a  little  outside  the  outline.  The  left 
hand  mass  of  light  takes  the  same  form  as  that  on  the  right,  only  the 
light  does  not  extend  up  or  down  quite  as  far.  At  each  extremity  a  star 
is  located.  The  vertices  of  the  great  or  general  outline  comparatively 
faint.  Several  stars  are  visible  on  the  nebula.  One  distinctly  seen  in 
the  center  of  the  right  hand  mass  of  light,  one  in  the  center  of  the 
principal  axis,  fainter  than  the  first  mentioned  ;  one  still  more  faint 
midway  between  these  two.  Another  is  seen  by  glimpses  below,  and  to 
the  right  of  the  one  first  mentioned.  There  are  besides  many  stars  in 
the  same  field  of  view." 

Lord  Rosse's  great  telescope  has  produced  no  great  change  in  the 
figure,  while  it  has  revealed  more  light  in  the  compressed  parts  of  the 
nebula.  Nichol  describes  it  as  having  "  no  longer  distinctness  of  com- 
pletion of  form,  but  a  strange  mass  internally  most  irregular,  cluster- 
ing apparently  around  two  principal  nuclei,  or  knots  of  stars,  and  pre- 
senting, where  it  merges  into  the  dark,  the  utmost  indehniteuess  of 
outline,"  and  yet  the  figure  has  an  outline  quite  as  well  defined  as  those 
usually  presented  in  drawings  of  this  object. 

I  his  object  is  doubtless  the  union  of  two  mighty  clusters  of  myriads 
of  suns,  and  as  the  double  stars  are  scattered  profusely  through  space, 
we  occasionally  find  what  may  be  justly  termed  double  nebulae  and 
double  clusters.  The  distance  of  this  object  must  be  absolutely  over- 
whelming, and  its  dimensions  beyond  the  powers  of  computation. 

It  may  be  picked  up  on  a  line  joining  f&  Cygni  and  the  Dolphin,  and 
about  7°  southeast  of  the  first  named  star.  The  angle  of  position  of 
the  line  joining  the  centers  of  the  nebulous  masses,  is  31°  08',  as 
measured  by  Capt  Smyth. 


SERPENT ARIUS,  VEL    OPHIUCUS.  181 

;!^'»;;-  *         'v##P**& 

DIRECTIONS  FOR  TRACING  THE  CONSTELLATION   ON 

MAP     NO.    XXII. 

SERPENTARIUS,  VEL  OPHIUCHUS — THE  SERPENT-BEARER. 

Favorably  situated  for  examination  in  June,  July, 
and  August. 

SERPENTARIUS,    VEL    OPHIUCUS. 

THE  SERPENT-BEARER  is  also  called  JEsculapius, 
or  tfye  god  of  medicine.  He  is  represented  as  a 
man  having  both  hands  clenched  in  the  folds  of  a 
prodigious  serpent,  which  is  writhing  in  his  grasp. 

The  constellation  occupies  a  considerable  space 
in  the  mid  heavens,  directly  south  of.  Hercules,  and 
west  of  Taurus  Poniatowski.  Its  center  is  very 
nearly  over  the  equator,  opposite  to  Orion,  and 
comes  to  the  meridian  the  26th  of  July.  It  con- 
tains seventy-four  stars,  including  one  of  the  2d 
magnitude,  five  of  the  3d,  and  ten  of  the  4th. 

The  principal  star  in  Serpentarius  is  called  Has 
Alhague,  marked  a.  It  is  of  the  2d  magnitude,  and 
situated  in  the  head,  about  5°  east-southeast  of 
Ras  Algethi,  marked  a,  in  the  head  of  Hercules. 
Ras  Alhague  is  nearly  13°  north  of  the  equinoctial, 
while  Rhoy  in  the  southern  foot,  is  about  25°  south 
of  the  equinoctial.  These  two  stars  serve  to  point 
out  the  extent  of  the  constellation  from  north  to 
south.  Ras  Alhague  comes  to  the  meridian  on  the 
28th  of  July,  about  21  minutes  after  Ras  Algethi. 

About  10°  southwest  of  Ras  Alhague  are  two  small  stars,  one  of  the 
3d,  the  other  of  the  4th  magnitude,  scarcely  more  than  a  degree  apart. 
They  distinguish  the  left  or  west  shoulder.  The  northern  one  is  marked 
Iota,  and  the  other  Kappa. 

Eleven  or  twelve  degrees  south-southeast  of  Ras  Alhague,  are  two 
other  stars  of  the  3d  magnitude,  in  the  east  shoulder,  and  about  2°  apart. 
The  upper  one  is  called  Cheleb,  or  £,  and  the  lower  one  Gamma. 

Q 


182  GEOGRAPHY  OF  THE  HEAVENS. 

These  stars  in  the  head  and  shoulders  of  Serpentarius  form  a  triangle, 
with  the  vertex  in  Ras  Alhague,  and  pointing  towards  the  northeast. 

About  4°  east  of  r,  is  a  remarkable  cluster  of 
four  or  five  stars,  in  the  form  of  the  letter  V,  with 
the  open  part  to  the  north.  It  very  much  resembles 
the  Hyades.  This  beautiful  little  group  marks  the 
face  of  TAURUS  PONIATOWSKI.  The  solstitial  colure 
passes  through  the  equinoctial  about  2°  east  of  the 
lower  star  in  the  vertex  of  the  V.  The  letter 
name  of  this  star  is  k.  There  is  something 
remarkable  in  its  central  position.  It  is  situated 
almost  exactly  in  the  mid  heavens,  being  nearly 
equidistant  from  the  poles,  and  midway  between 
the  vernal  and  autumnal  equinoxes.  It  is,  how- 
ever, about  one  and  a  third  degrees  nearer  the 
north  than  the  south  pole,  and  about  two  degrees 
nearer  the  autumnal  than  the  vernal  equinox, 
being  about  two  degrees  west  of  the  solstitial  colure. 

Directly  south  of  the  V,  at  the  distance  of  about  12°,  are  two  very 
small  stars,  about  2°  apart,  situated  in  the  right  hand,  where  it  grasps 
the  serpent.  About  halfway  between,  and  nearly  in  a  line  with  the 
two  in  the  hand  and  the  two  in  the  shoulder,  is  another  star  of  the  3d 
magnitude,  marked  Ztta,  situated  in  the  Serpent,  opposite  the  right 
elbow.  It  may  be  known  by  means  of  a  minute  star  just  under  it. 

Marsic,  marked  A,  in  the  left  arm,  is  a  star  of  the  4th  magnitude, 
about  10°  southwest  of  /  and  x  .  About  7°  farther  in  the  same  direc- 
tion, are  two  stars  of  the  3d  magnitude,  situated  near  the  hand,  and 
a  little  more  than  a  degree  apart.  The  upper  one  of  the  two,  which  is 
about  1 6°  north  of  Graffias  in  Scorpio,  is  called  Yed,  marked  ef,  the 
other  is  marked  s .  These  two  stars  mark  the  other  point  in  the  folds  of 
the  monster  where  it  is  grasped  by  Serpentarius. 

The  left  arm  of  Serpentarius  may  be  easily  traced  by  means  of  the 
two  stars  in  the  shoulder,  the  one  (x)  near  the  elbow,  and  the  other 
two  in  the  hand ;  all  lying  nearly  in  a  line  north-northeast,  and  south- 
southwest.  In  the  same  manner  may  the  right  arm  be  traced,  by  stars 
very  similarly  situated  ;  that  is  to  say,  first  by  the  two  in  the  east 
shoulder,  just  west  of  the  V,  thence  8°  in  a  southerly  direction  inclin- 
ing a  little  to  the  east,  by  £•  (known  by  a  little  star  right  under  it),  and 
then  by  the  two  small  ones  in  the  right  hand,  situated  about  6°  below  £ 

About  12°  from  Antares,  in  an  easterly  direction,  are  two  stars  in  the 
right  foot,  about  2°  apart.  The  largest  and  lower  of  the  two,  is  on  the 
left  hand.  It  is  of  between  the  3d  and  4th  magnitudes,  and  marked  p . 
There  are  several  other  stars  in  this  constellation,  of  the  3d  and  4th 
magnitudes.  They  may  be  traced  out  from  the  maps. 


SERPENTARIUS,  VEL   OPHIUCHUS.  183 

TELESCOPIC     OBJECTS. 

/>  OPHIUCHI.— A.  R.  =  16  h.  16  m.  00  s.  Dec.  =  —  23O  04'  03". 
A  fine  double  star,  on  the  Serpent  Bearer's  foot.  A  5,  B  7£  magnitude. 

Pos.  3°  01'         Dis.  3".08         Epoch  1832.38 

Discovered  by  Sir  W.  Herschel,  1 780.  There  is  but  little  evidence  of 
any  physical  connection  between  the  components. 

*.  OPHIUCHI,  a  binary  star. — A-  R.  =  16  h.  22  m.  51  s.     Dec.  -f-  2° 

20'  04".     A  4,  B  6,  magnitude.  The  following  measures  are  recorded : 

Pos.    75030'         Dis.  0".50  Epoch   1783.18     Herschel. 

331   48                    0.84  1825.51     Struve, 

356  05                   1  .00  1839.67     Smyth. 

2  47  8"              1  .29  1841.59     Madler. 

3  42                    1  .42  1847.65     Mitchel. 

From  these  observations,  it  is  evident  that  the  stars  are  revolving  about 
their  common  center  of  gravity,  in  a  period  of  about  120  years. 

T  OPHIUCHI.— A.  R.  =  17  h.  54  m.  22  s.  Dec.  =  —  8°  10'  04". 
A  very  close  binary  star,  on  the  right  hand  of  Ophiuchus,  the  closest  of 
Herschel's  double  stars. 

Discovered,  April,  1783.  A  5,  B  6,  magnitude.  A  third  star,  dis- 
tant 83",  in  the  same  field  of  view. 

The  following  measures  will  exhibit  the  progressive  changes : 

Pos.  3310  36'         Dis.  elongated         Epoch  1783.27     Herschel. 
199     54  0".436  1836.62     Struve. 

225     36  0  .772  1842.57     Mildler. 

229     24  0  .779.  1846.51     Mitchel. 

Miidler  remarks,  with  reference  to  this  system,  as  follows :  »«  The  pe- 
riodic time  must  be  about  110  years.  The  inclination  and  eccentricity 
appear  to  be  considerable.  The  distance  was  a  minimum  in  1825,  or  a 
short  time  before.  It  has  regularly  increased  ever  since.  It  is  hoped 
that  observations  further  south  than  Derpat  may  follow  this  binary  sys- 
tem with  attention." 

Combining  all  the  observations,  a  shorter  period  seems  to  be  indicated, 
perhaps  not  exceeding  90  years.  The  yearly  change  in  the  angle  of 
position,  from  1827  to  1846,  amounts  to  4O  33'. 

70,  or  p  OPHIUCHI.— A.  R.  =  17h.57m.  22s.  Dec.  =  -f-  2O  32'  06" 
A  swiftly  revolving  binary  system.  A  4£,  B  7,  magnitude. 

This  star  has  engaged  the  attention  of  many  distinguished  astrono- 
mers. The  rapidity  of  its  motion  excited  the  notice  of  its  discoverer, 
and  caused  the  following  record :  "  The  alteration  of  the  angle  of  posi- 
tion that  has  taken  place  in  the  angle  of  position  of  this  double  star  is 
remarkable.  October  7,  1779,  the  stars  were  exactly  in  the  same  paral- 
lel, the  preceding  star  being  largest.  September  24,  1781,  it  was  9°  14', 
n  f ;  and,  May  29,  1804,  it  was  48°  01',  n  p;  which  gives  a  change 
of  131°  59',  in  24  years  and  254  days."  The  orbit  has  been  computed 
by  several  astronomers;  but  with  the  greatest  care,  recently,  by  M. 
Miidler,  who  has  reached  the  extraordinary  conclusion,  that  these  re- 


184  GEOGRAPHY  OF  THE  HEAVENS. 

volving  stars  are  moving  under  the  disturbing  influences  of  some  third 
body,  as  yet  undiscovered. 

Midler's  elements  are  the  following  : 
Periastre  passage,  T  =  1812.73 
Periodic  time,  P  ==  92.869  years. 

The  angle  between  the  maj.  axis  and 

line  of  nodes,  .  >,-  .  *#  \  =  142°  05'    08" 

Eccentricity,  -  -          e  =  0.4438 

Mean  annual  angle  of  motion,  m  =  232.584 

Angle  of  position,  -         ^  =  126    47     02 

Inclination  of  the  plane  of  the  orbit,  t==    64     51     04 

The  following  measures  will  show  the  changes  which  have  occurred  • 
Pos.    90°  00'         Dis.  3".  59         Epoch  1779.77     Herschel. 
157    86  3  .79  1821.74     Striive. 

137    20  5  .53  1830.57     Dawes. 

178    54  6  .44  1837.52     Bessel. 

175    26  6  .38  1841.53-    Midler. 

120    45  6  .53  1847.55     Mitchel. 

The  discrepances  between  computation  and  observation,  ascribed  by 
Miidter  to  the  influence  of  some  unknown  disturbing  body,  have  been 
recently  attributed  to  aberration,  produced  by  the  motion  of  the  stars  in 
their  orbits.  This  matter  is  yet  in  a  state  of  uncertainty. 

There  are  many  double  stars  in  this  constellation,  which  will  be  readily 
found  on  the  charts,  distinguished,  as  usual,  by  their  round  furm, — all 
other  stars  being  angular,  or  star-shaped.  Under  favorable  circumstances, 
all  stars  appear  round,  and  disk-like,  in  large  and  perfect  instruments. 

A  RICH  GLOBULAR  CLUSTER. — A.  R.  =  16h.  38m.  56s.  Dec. 
=  _  10  40'  03".  This  object' I  have  repeatedly  examined.  It  nearly 
fills  the  field  of  view,  with  a  power  of  250,  its  diameter  being  from  7  to 
8  minutes  of  space.  There  are  three  bright  stars  in  the  cluster,  with 
many  smaller  but  prominent  ones  scattered  in  the  field. 

Messier  discovered  it,  in  1764,  but  saw  no  stars.  Herschel  locates  it  at 
the  distance  186.  It  may  be  found  nearly  on  the  line  joining  i  and  & 
and  8$°  distant  from  the  first  star.  It  is  represented  in  the  Bedford 
Catalogue  as  greatly  condensed  at  the  center.  I  find  this  remark 
scarcely  applicable  to  its  appearance,  as  seen  with  the  12  inch  refractor. 
The  resolution  is  complete. 

A  CLUSTER  OF  COMPRESSED  STARS. — A.  R.  =  16  h.  48  m.  45s. 
Dec.  =  —  3°  51'  08".  Discovered  by  Messier,  1764,  and  by  him  de- 
scribed as  a  beautiful  round  nebula.  It  is  easily  resolved,  and,  under  a 
full  aperture  of  12  inches,  is  a  noble  object.  There  are  three  pretty  dis- 
tinct star-like  radiations,  running  out  from  the  center,  and  four  or  five 
little  patches  of  separate  stars  in  the  same  field  of  view.  It  follows  « 
Ophiuchi,  on  the  same  parallel  nearly,  and  about  8°  distant.  Sir  W 
Herschel  makes  its  profundity  of  the  243d  order. 

A  LAROI  GLOBULAR  CLUSTER. — A.  R.  =  17  h.  29  m.  13  s.  Dec. 
—  __  30  00'  09".  Sir  William  Herschel  describes  this  object  as  follows : 


SERPENTARIUS,   VEL    OPHIUCUS.  185 

"  Extremely  bright,  round,  easily  resolvable.  With  a  power  of  500,  I 
can  see  the  stars.  The  heavens  are  pretty  rich  in  stars  of  a  certain  size, 
but  they  are  larger  than  those  in  the  cluster,  and  easily  to  be  distinguished 
from  them.  This  cluster  is  considerably  behind  the  scattered  stars,  as 
some  of  them  are  projected  on  it.  From  the  observations  of  the  20 
feet  telescope,  which  had  the  power  of  discerning  objects  75.08  times  as 
far  as  the  eye,  the  profundity  of  this  cluster  must  be  of  the  900th  order." 
This  cluster  may  be  found  6£°  south  by  west  from  y  Ophiuchi,  nearly 
midway  from  /3  Scorpii  and  the  tail  of  Aquila.  It  is  a  fine  object, 
large  and  well  defined. 

A  LARGE  AND  EASILY  RESOLVED  CLUSTER. — A.  R.  =  17h.  47m. 
32  s.  Dec.  =  —  18°  58'  02",  between  the  left  leg  of  Ophiuchus  and 
the  bow  of  Sagittarius. 

Discovered  by  Messier,  1 764.  It  is  on  a  line  northwest  from  p.  Sa- 
gittarii,  and  distant  about  5°. 

A  CLOSE  DOUBLE  STAR. — A.  R.  16  h.  54  m,  18  s.  Dec.  =  -\- 
8°  41'  03".  On  the  right  shoulder.  A  7,  B  8. 

Pos.  135040'         Dis.  1".34          Epoch  1830.97    Striive. 
137    00  1  .50  1832.41     Smyth. 

146    57  0  .826  1847.70     Mitchel. 

These  last  measures  would  indicate  binary  character,  and  I  am  con 
fident  that  they  were  well  made. 

36  OPHIUCHI.— A.  R.  =  17  h.  05  m,  29  s.  Dec.  =  —  26°  21'  05* 
A  double,  or  rather,  multiple,  star,  between  the  left  foot  and  the  Scor 
pion's  tail.  A  4^,  B  6£,  magnitude. 

Pos.  213020         Dis.  5".32         Epoch  1843.52     Airy. 
215    49  4  .27  1847.62     Mitchel. 

73  OPHIUCHI,— A.  R.  =  18  h.  01  m.  37  s.  Dec.  =  -f-  30  58'  03" 
Between  the  left  shoulder  of  Ophiuchus  and  the  Serpent's  tail.  A  6,  B 
7£,  magnitude. 

Discovered  by  Herschel. 

Pos.  2670  12'         Dis.  0".90  Epoch   1783.32     Herschel. 

257    37  1  .98  1822.46     Her.  &  South. 

259    44  1  .54  1831.05     Struve. 

255    00      .  1  .40  1842.00     Smyth. 

253    00  1  .274  1847.55     Mitchel. 

Here  is  certainly  a  binary  system.  The  early  measures  of  Sir  W. 
Herschel,  as  well  as  those  by  Herschel  and  South,  are  discordant  with 
the  later  measures.  From  1831  to  1847,  a  period  of  16  years,  there  has 
been  a  change  of  6°.  The  motion  is  retrograde. 

A  DOUBLE  STAR.— A.  R.  =  17  h.  17  m.  21  s.     Dec.  =  -j-  15O  45' 
04".     Between  the  heads  of  Ophiuchus  and  Hercules.     A  7,  B  13. 
Discovered  by  Struve. 

Pos.  610  54'         Dig.  4»<073         Epoch  1830.23     Struve. 
62    33  3  .654  1847.60     Mitchel. 

These  observations  imply  fixity  in  this  set. 


186  GEOGRAPHY  OF  THE  HEAVENS. 

88  P.  XIV,  OPHIUCHI.— A.  R.  =  16  h.  20  m.  10s.     Dec.  =  —  7° 
45'  09".     A  delicate  double  star,  near  the  right  thigh  of  Ophiuehus. 
A  7£,  B  12.     Reckoned  a  difficult  object,  from  the  small  size  of  B. 
Pos.  302°  44'         Dis.  4"  .687         Epoch   1831.48     Striive. 
305    00  5   .000  1833.47     Smvth. 

304     14  5   .292  1817.70     L.  M. 

There  is  strong  evidence  of  fixity  in  these  measures,  and  there  is  little 
reason  to  believe  that  these  stars  are  otherwise  than  optically  related. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.   XXIII. 

PEGASUS — THE  FLYING  HORSE. 
EQUULUS — THE  HORSE'S  HEAD. 

Favorably  situated  for  examination  in  September,  Oc- 
tober, November  and  December. 

PEGASUS. 

THE  FLYING  HORSE. — This  constellation  is  repre- 
sented in  an  inverted  posture,  with  wings.  It  occu- 
pies a  large  space  in  the  heavens,  between  the 
Swan,  the  Dolphin  and  the  Eagle,  on  the  west; 
and  the  Northern  Fish  and  Andromeda,  on  the  east. 
Its  mean  right  ascension  is  340°,  or,  it  is  situated 
20°  W.  of  the  prime  meridian.  It  extends  from  the 
equinoctial  N.  35°.  Its  mean  length,  E.  and  W.,  is 
about  40°,  and  it  is  six  weeks  in  passing  our  meri- 
dian, viz.  from  the  1st  of  October  to  the  10th  of 
November. 

We  see  but  a  part  of  Pegasus,  the  rest  of  the  ani- 
mal being,  as  the  poets  imagined,  hid  in  the  clouds. 

It  is  readily  distinguished  from  all  other  constel- 
lations by  means  of  four  remarkable  stars,  about 
15°  apart,  forming  the  figure  of  a  square,  called  the 
square  of  Pegasus.  The  two  western  stars  in  this 
square  *come  to  the  meridian  about  the  23d  of 


CONSTELLATION  OF  PEGASUS.        187 

October,  and  are  about  13°  apart.  The  northern 
one,  which  is  the  brightest  of  three  triangular  stare 
in  the  martingale,  is  of  the  second  magnitude,  and  is 
called  Scheat,  marked  0.  Its  declination  is  26f  °  N. 
Markab,  marked  a,  also  of  the  second  magnitude, 
situated  in  the  head  of  the  wing,  is  13°  S.  of  Scheat, 
and  passes  the  meridian  11  minutes  after  it. 

The  two  stars  which  form  the  eastern  side  of  the 
square,  come  to  the  meridian  about  an  hour  after 
those  in  the  western.  The  northern  one  has  al- 
ready been  described  as  Alpheratz,  or  a,  in  the  head 
of  Andromeda ;  but  it  also  belongs  to  this  constel- 
lation, and  is  14°  E.  of  Scheat.  14°  S.  of  Alphe- 
ratz,  is  Algenib,  a  Persei  (see  Map  No.  I),  the  last 
star  in  the  wing,  situated  6£°  E.  of  Markab. 

Algenib,  in  Pegasus,  Alpheratz,  in  Andromeda,  and  Caph,  in  Cas- 
siopeia, are  situated  on  the  prime  meridian,  and  point  out  its  direction 
through  the  pole.  For  this  reason,  they  are  sometimes  called  the  three 
guides.  They  form  an  arc  of  that  great  circle  in  the  heavens  from  which 
the  distances  of  all  the  heavenly  bodies  are  measured.  It  is  an  arc  of 
the  equinoctial  colure,  which  passes  through  the  vernal  equinox,  and 
which  the  sun  crosses  about  the  21st  of  March.  It  is,  in  astronomy, 
what  the  meridian  of  Greenwich  is  in  geography.  If  the  sun,  or  a 
planet,  or  a  star,  be  said  to  have  so  many  degrees  of  right  ascension,  it 
means  that  the  sun  or  planet  has  ascended  so  many  degrees  from  this 
prime  meridian. 

Enif,  marked  «,  sometimes  called  Enir,  is  a  star  of  the  third  magni- 
tude, in  the  nose  of  Pegasus,  about  20°  W.  S.  W.  of  Markab,  and  half 
way  between  it  and  the  Dolphin.  About  one-third  of  the  distance  from 
Markab  towards  Enif,  but  a  little  to  the  S.  there  is  a  star  of  the  3d  mag- 
nitude, in  the  neck,  whose  letter  name  is  Zeta.  The  loose  cluster  di- 
rectly S.  of  a  line  joining  Enif  and  Zeta,  forms  the  head  of  Pegasus. 

In  this  constellation,  there  are  eighty-nine  stars 
visible  to  the  naked  eye,  of  which  three  are  of  the 
second  magnitude,  and  three  of  the  third. 

TELESCOPIC    OBJECTS. 

A  DOUBLE  STAR.— A.  R.  =  21  h.  14  m.  41  s.  Dec.  =  19  o  or 
04",  between  the  head  of  Pegasus  and  the  hind  legs  of  the  Fox.  A  4, 
considered  variable ;  B  9,  magnitude.  • 

Pos.  310008'        Dis.  36".4        Epoch  1333.95 


188  GEOGRAPHY  OF  THE  HEAVENS. 

Although  no  sensible  change  has  yet  been  discovered  in  this  set,  a 
common  proper  motion  would  indicate  some  physical  union. 

A  LARGE  AWD  BRILLIANT  CLUSTER. — A.  R.  =  21  h.  22  m.  13s. 
Dec.  =  -{-  1 10  27'  04",  between  the  mouths  of  Pegasus  and  Equulus. 

Discovered  by  Meraldi,  1745,  and  described  by  him  as  "  a  nebulous 
star,  quite  bright,  and  composed  of  several  stars." 

It  was  fully  resolved  by  Sir  William  Herschel,  1783,  and  placed  by 
him  in  the  243d  order  of  distances.  This  object  is  greatly  condensed  at 
the  center,  and  has  many  radiations. 

There  is  a  great  condensation  at  the  center,  and  even  a  brilliant 
nucleus,  around  which  the  stars  are  scattered  in  rich  profusion  for  a 
distance  of  about  2'  in  diameter.  Beyond  this  the  cluster  is  less  rich  in 
stars.  The  space  preceding  the  cluster  is  nearly  vacant.  The  follow- 
ing space  is  tolerably  well  filled  with  stars. 

A  SMALL  DOUBLE  STAR.— A.  R.  =  22  h.  06  m  37  s.  Dec.  =  -f- 
160  24'  02",  between  the  head  and  legs  of  Pegasus.  A  7£,  B  lO^. 
The  first  yellow,  the  second  green. 

Discovered  by  Striive. 

Pos.  316°  24'        Dis.  7".63        Epoch  1828.95     Striive. 
331     29  8  .03  1847.65     Milchel. 

This  is  certainly  a  binary  system. 

37  PEGASI.—A.  R.  =  22  h.  21  m.  53  s.     Dec.  =  -f  03°  37'  03", 
a  binary  star  on  the  mane  and  near  the  head  of  Pegasus.     A  6,  B  7£. 
Discovered  by  Striive. 

Pos.  112°  36'         Dis.   1".36         Epoch  1831.12     Struve. 
118     54  I  .10  1839.66     Smyth. 

121     46  0  .98  1847.70     Mitchel. 

Here  is  strong  evidence  of  binary  character,  as  the  angular  velocity 
has  been  on  the  increase,  and  the  distance  is  certainly  diminishing. 

55  H.  L,  PEGASI.— A.  R.  =  22  h.  56  m.  58  s.  Dec.  =  -J-  11°  27' 
09",  an  elongated  nebula  in  the  Horse's  mane. 

Discovered  by  Herschel  in  1784. 

This  is  an  exceedingly  faint  and  difficult  object.  I  examined  it  care- 
fully in  September,  1847,  and  although  it  was  readily  found,  it  required 
very  close  gazing  to  make  any  thing  out  of  it.  It  stretches  between  two 
stars,  the  upper  one  of  which  is  not  touched  by  the  nebulous  matter. 
A  minute  telescopic  star  just  precedes  the  upper  extremity  of  the  nebu- 
lous matter,  which  seems  to  have  been  overlooked  by  preceding  observ- 
ers. There  is  something  of  a  glow  at  the  center  after  long  gazing,  and 
under  a  side  glance. 

This  object  is  thought  to  be  a  flat  ring  seen  obliquely.  It  is  one  of 
the  most  difficult  objects  in  the  heavens,  and  requires  a  powerful  instru- 
ment for  satisfactory  examination. 


EQUULUS,   VEL  EQUI  SECTIO.  189 


EQUULUS,  VEL    EQUI  SECTIO. 

THE  LITTLE  HORSE,  OR  THE  HORSE'S  HEAD.  —  This 
Asterism,  or  small  cluster  of  stars,  is  situated  about 
7°  west  of  Enif,  in  the  head  of  Pegasus,  and  about 
halfway  between  it  and  the  Dolphin.  It  is  on  the 
meridian  at  8  o'clock  on  the  llth  of  October.  It 
contains  ten  stars,  of  which  the  two  principal  are 
only  of  the  4th  magnitude.  These  may  be  readily 
distinguished  by  means  of  the  long  irregular  square 
which  they  form.  The  two  in  the  nose,  are  much 
nearer  together  than  the  two  in  the  eyes;  the 
former  being  1°  apart,  and  the  latter  2?°.  Those 
in  the  nose  are  uppermost,  being  4°  north  of  those 
in  the  eyes.  This  figure  also  is  in  an  inverted  posi- 
tion. These  four  stars  are  situated  10°  or  Ii2° 
southeast  of  the  diamond  in  the  Dolphin's  head. 
Both  of  these  clusters  are  noticeable  on  account  of 
their  figure  rather  than  their  brilliancy. 

TELESCOPIC    OBJECTS. 

376  P.  XX,  EQ.UULEI.P—  A.  R.  =  20  h.  47  m.'  40  s.  Dec.  =  -j- 
03°  55'  06",  a  close  double  star  between  the  Horse's  head  and  the  bow 
of  A  ruinous.  A  6,  B  8,  magnitude. 

Discovered  by  Struve. 

Pos.  289°  10'         Dis.  1".8         Epoch  1829.48     Struve. 
.   287     45        +       1  .874  1847.65     Mitchel. 

These  measures  may  possibly  indicate  a  slow  retrograde  motion,  a 
change  of  2°  about  in  18  years.  This  would  give  an  annus  magnus 
to  the  system  of  more  than  4000  years. 


A.  R.  =  20  h.  51  m.  05  s.    Dec.  =  03°  41'  01",  a 
delicate  triple  star,  preceding  the  Horse's  forehead.     A  5^,  B  7£. 
Discovered  to  be  double  by  Herschel  ;  subdivided  by  Struve. 
Pos.  A  B  290°  00'        Dis.  0".50         Epoch  1838.83  Smyth. 
288     06  0  .574  1847.60  Mitchel. 

AC    84     21  9  .37  1780.59  Herschel. 

79     21  12  .37  1823.58  Her.  &  South. 

78     01  11  .20  1838.83  Smyth. 

76     25  It  .08  1847.60  Mitchel. 

These  measures  determine  the  binary  character  of  A  and  C,  which  is 
likewise  rendered  more  certain  by  the  equality  of  their  proper  motion. 


190       £          GEOGRAPHY  OF  THE  HEAVENS. 

Here  we  are  presented  with  a  magnificent  system.  Three  suns  revolv- 
ing about  their  common  center  of  gravity,  and  sweeping,  together  with 
their  trains  of  planets  and  comets,  through  the  regions  of  space. 

A  EQ.UULEI.— A.  R.  =  20  h.  54  rn.  19  s.     Dec.  =  -f-  06°  33'  03". 
A  fine  double  star  preceding  the  Horse's  nose.      A  6,  B  6^,  magnitude. 
Discovered  by  Striive. 

Pos.  2250  36'         Dis.  2".6         Epoch  1833.72     Smyth. 
227     42  I  .9  1847.60     Mitchel. 

These  observations  are  not  sufficient  to  determine  the  binary  character. 


DIRECTIONS  FOR  TRACING  THE  CONSTELLATIONS  ON 

MAP    NO.  XXIV. 

AQUARIUS — THE  WATER-BEARER. 
CAPRICORNUS — THE  GOAT. 

Favorably  situated  for  examination  in  September, 
October,  November  and  December. 

AQUARIUS. 

THE  WATER-BEARER. — This  constellation  is  rep- 
resented by  the  figure  of  a  man,  pouring  out  water 
from  an  urn.  It  is  situated  in  the  Zodiac,  immedi- 
ately south  of  the  equinoctial,  and  bounded  by  the 
Little  Horse,  Pegasus,  and  the  Western  Fish  on  the 
north,  the  Whale  on  the  east,  the  southern  Fish  on 
the  south,  and  the  Goat  on  the  west.  It  is  now 
the  12th  in  order,  or  last  of  the  Zodiacal  constella- 
tions ;  and  is  the  name  of  the  llth  sign  in  the 
ecliptic.  Its  mean  declination  is  14°  south,  and  its 
mean  right  ascension  335°,  or  22  hours,  20  min.;  it 
being  1  hour  and  40  min.  west  of  the  equinoctial 
colure  ;  its  center  is,  therefore,  on  the  meridian  the 
15th  of  October. 

It  contains  one  hundred  and  eight  stars  ;  of  which 
toe  four  largest  are  all  of  the  3d  magnitude. 


CONSTELLATION  OF  AQUARIUS*         ^f    191 

"  His  head,  his  shoulders,  and  his  lucid  breast, 
Glisten  with  stars ;  and  where  his  urn  inclines, 
Rivers  of  light  brighten  the  wat'ry  track." 

The  northeastern  limit  of  Aquarius  may  be 
readily  distinguished  by  means  of  three  stars  of 
the  4th,  and  one  of  the  5th  magnitude,  in  the  hand 
and  handle  of  the  urn,  so  placed  as  to  form  the 
letter  Y,  very  plainly  to  be  seen,  15°  southeast  of 
Enif,  or  *  Equulei,  or  18°  S.  S.  W.  of  Markab,  in 
Pegasus ;  making  with  the  two  latter  nearly  a  right 
angle. 

About  4£°  west  of  this  figure  is  El  Melik,  marked  a.,  a  star  of  the 
3d  magnitude,  in  the  east  shoulder,  and  the  principal  one  in  this  con- 
stellation. 10°  southwest  of  a.,  is  another  star  of  the  same  magnitude, 
situated  in  the  west  shoulder,  called  Sad  es  Saud,  marked  @. 

Ancha,  marked  6,  of  the  5th  magnitude,  is  in  the  right  side,  8°  south 
of  A.  9°  east  of  6,  is  another  star  of  the  4th  magnitude,  whose  letter 
name  is  Lambda. 

Scheat,  marked  cf,  of  the  3d  magnitude,  lying  below  the  knee,  is 
situated  8^°  south  of  x;  and  14  south  of  «f,  the  brilliant  star  Fomalhaut, 
of  the  1st  magnitude,  terminates  the  cascade  in  the  mouth  of  the 
Southern  Fish.  This  star  is  common  to  both  these  constsellations,  and 
is  one  of  those  from  which  the  lunar  distance  is  computed  for  ascer- 
taining the  longitude  at  sea.  It  culminates  at  9  o'clock  on  the  22d  of 
October. 

Fomalhaut,  Deneb  Kaitos,  and  Alpha  in  the  head  of  Phoenix,  make 
a  large  triangle,  whose  vertex  is  in  Deneb  Kaitos.  Those  two  stars  of  the 
4th  magnitude,  situated  4°  south  of  @,  and  nearly  the  same  distance 
from  6  ,  are  in  the  tail  of  Capricorn.  They  are  about  2°  apart.  The 
western  one  is  called  Deneb  Algedi. 

The  rest  of  the  stars  in  the  cascade  are  quite  small ;  they  may  be 
traced  from  the  letter  Y,  in  the  urn,  in  a  southeasterly  direction  towards 
the  tail  of  Cetus,  from  which  the  cascade  suddenly  bends  off  near  eF, 
in  an  opposite  course,  and  finally  disappears  in  the  mouth  of  the  South- 
ern Fish,  30°  south  of  Y. 

TELESCOPIC     OBJECTS. 

4  AauARii.— A.  R.  =  20  h.  42  m.  57  s.     Dec.  =  —  6°  13'  02".      - 
A  close  binary  star,  between  Aquarius  and  Equuleus.    A  6,  yellow  ;  B 
8,  purple. 

Discovered  by  Sir  W.  Herschel. 

The  following  measures  are  the  only  ones  which  I  have  been  able 
to  find. 

Pos.  3510  30'       Dis.  00".30        Epoch  1782.68     Herschel. 
25    07  00  .81  1825.59     Struve. 

24    36  00  .6  1841.51     Mitdler. 


Vf 

192    '  -fr          GEOGRAPHY  OF   THE  HEAVENS. 

A  PLANETARY  NEBULA. — A.  R.  =  20  h.  55  m.  27  s.  Dec.  =  — 
110  59' 00".  in  ^  middle  of  the  Scarf  of  Aquarius.  It  maybe 
found  nearly  on  the  parallel  of  <*  Capricorni,  and  12°  east  of  it. 

Discovered  by  Sir  William  Herschel  in  1782. 

Its  diameter  amounts  to  no  less  than  20".  The  surface  evenly  tinted 
and  of  a  delicate  pale  blue.  Its  disk  is  comparatively  well  defined,  and  the 
tint  resembles  that  of  Uranus  and  Neptune.  Its  distance  must  be  equal 
to  that  of  the  fixed  stars,  as  it  has  no  annual  parallax.  Its  diameter, 
therefore,  cannot  be  less  than  three  thousand  millions  of  miles.  I  have 
frequently  examined  this  wonderful  object,  and  on  the  9th  of  September, 
1847,  found  its  diameter  to  be  about  9"  or  10".  The  upper  part  ia 
wanting  in  roundness,  giving  it  the  appearance  of  an  obtuse  crescent 

12  AQ.UARII — A.  R.  =  20  h.  55  m/37  s.  Dec,  =  —  06°  27'  00". 
A  close  double  star  in  the  space  between  the  Scarf  of  Aquarius,  and  the 
head  of  Equuleus.  A  5£,  white  ;  B  8£,  light  blue. 

Discovered  by  Striive. 

Pos.  1890  36'        Dis.  02".66         Epoch  1831.31     Striive. 
191     00  02  .80  1831.82     Smyth. 

191     30  08  .23  1847.63     Mitchel. 

There  is  something  extraordinary  about  this  star.  The  distance 
obtained  by  my  measures  is  nearly  four  tirm  s  as  great  as  that  in  the 
books ;  and  the  star  B  instead  of  being  of  the  8£  magnitude,  is  certainly 
as  low  as  the  15th.  I  satisfied  myself  of  this  by  turning  the  instrument 
on  yg  Aquarii,  whose  companion  is  of  the  15th  magnitude.  The  star 
may  be  variable,  but  the  increase  of  distance  is  unaccountable. 

£  AauABiT— A.  R.  =  21  h.  23  rn.  07.     Dec.  =  —  06O  16'  00", 
on  the  right  shoulder  of  Aquarius.     A  3,  yellow  ;  B  15,  blue. 
Discovered  by  Herschel,  who  gave  the 
Pos.  325°  48'         Dis.  uncertain.         Epoch  1 782 

370     00  02".00  1833     Smyth. 

This  last  is  a  mere  estimation.  :f  !,. 

29  AQ.UARII.— A.  R.  =  21  h.  53  m.  41  s.  Dec.  =  —  17°  43* 
09".  A  beautiful  double  star  on  the  tail  of  Capricorn.  A  6,  B  8, 
magnitude. 

Pos.  2430  34'         Dis.  04".50         Epoch  1823.19     Striive. 
242    08  04  .466  1847.70     Mitchel. 

These  measures  decide  the  character  of  the  star.  The  components 
must  be  optically  united. 

A  FIXE  GLOBULAR  CLUSTER — A.  R.  =  21  h.  25  m.  10  s.  Dec. 
— :  —  01°  32'  01";  on  the  neck  of  Aquarius. 

Discovered  by  Meraldi  in  1 746,  more  than  a  hundred  years  ago,  and 
among  the  first  known  nebula. 

It  was  fully  resolved  by  Sir  William  Herschel,  with  his  40  feet 
reflector,  when  the  entire  mass  was  found  to  consist  of  myriads  of 
stars,  ranged  in  a  compressed  form,  and  closely  clustering  about  the 
center.  He  estimated  its  profundity  as  of  the  243d  order.  This  object 


CONSTELLATION   OF   AQUARIUS.  193 

was  examined  with  a  power  of  250,  and  a  12  inch  aperture,  on  the 
evening  of  the  9th  of  September,  1845,  and  described  as  follows.  The 
cluster  enters  the  field  in  great  beauty.  It  is  distinctly  resolved,  though 
the  stars  composing  it  are  very  minute,  with  great  condensation  at  and 
around  the  center.  The  diameter  of  the  brightest  portion  is  about  2'  by 
estimation.  A  coarse  double  star  follows  above  the  cluster.  Several 
bright  stars  in  the  field.  There  are  no  radiations  of  stars,  the  mass 
being  nearly  globular,  with  an  outline  somewhat  broken. 

41  AauARir A.  R.  =  22  h.  05  m.  27  s.  Dec.  =  —  21O  51'  00". 

A  double  star  between  the  Water-bearer  and  the  Southern  Fish.  A  6, 
B  8£,  magnitude. 

Discovered  by  Herschel,  bul  registered  by  him  without  measures. 

Pos.  1200  42'  Dis.  05".17  Epoch  1823.78  Herschel  &  South. 
120  22  04  .326  1847.70  Mitchel  &  L. 

An  interval  of  24  years  between  these  measures,  indicates  the  fixity 
of  the  components  of  these  stars. 

£  AauARii.-— A.  R.  =  22  h.  20  m.  35  s.     Dec.  =  —  00°  50'  02". 

A  binary  star  on  the  left  wrist  of  Aquarius.     A  4,  B  4£,  magnitudes. 

Discovered  by  Herschel  in   1779,  and  found  to  be  binary  as  early  as 

1804. 

Pos.  3550  14'        Dis.  03".525         Epoch  1830.98     Bessel. 
352    43  03  .389  1836.05    Struve. 

352     10  04  .123  1841.48     Miidler. 

348     54  02  .70  1842.59     Smyth. 

346     42  03  .948  1847.70     Mitchel. 

The  last  measures  but  one  seem  to  be  in  error  both  in  distance  and 
position.  Miidler  thinks  the  period  of  this  system  may  be  about  780 
years.  My  own  measures  were  confirmed  by  those  of  my  assistant,  the 
readings  agreeing  admirably  with  each  other. 

A  CLOSE  DOUBLE   STAR.— A.  R.  =  22  h.  34  m.  40  s.     Dec.  = 
—  9°  08'  08".  near  the  stream  issuing  from  the  vase  and  near  the 
vase's  mouth.     A  7,  B  8£,  magnitude. 
Discovered  by  Herschel. 

Pos.  311°  12'        Dis.  03".00         Epoch  1782.74     Herschel. 
:<17     22  1821.92     Striive. 

313'   08  02  .7  1838.67     Smyth. 

314     35  01  .82  1847.70     Mitchel. 

The  distance  in  this  set  seems  to  be  diminishing,  and  a  revolution  in 
an  orbit  whose  plane  is  nearly  coincident  with  the  visual  ray  appears 
probable. 

T  AQ.UARIT.— A.  R.  =  22  h.  39  m.  13  s.     Dec.  =—  14°  53'  09". 
Above  the  left  knee  of  Aquarius.     A  6,  B  9£,  magnitude. 
Discovered  by  Herschel  in  1782. 

A  TRIPLE  STAR.— A.  R.  =  22  h.  39  m.  35  s.  Dec.  =  — &o  03* 
05".  In  the  mouth  of  the  vase.  A  7£,  B  8,  C  9,  magnitude, 

R 


194  GEOGRAPHY  OF  THE   HEAVENS. 


94  AatTARii.—  A.  R.  =  23  h.  10  m.41  s.  Dec.  =  —  HO  19'  07  . 
In  the  space  between  the  stream  and  the  left  knee  of  Aquarius.  A  6, 
B  8£,  magnitude. 

Discovered  by  Piazzi. 

107  AQ.UAHII.—  A.  R.  =  23  h.  37  m.  42  s.  Dec.  =  —  19°  34' 
01".  Near  the  center  of  the  stream  flowing  from  the  urn.  A  6,  white; 
B  7^,  blue. 

Discovered  by  Herschel  in  1780. 


CAPRICORNUS. 

THE  GOAT. — This  is  the  tenth  sign,  and  eleventh 
constellation,  in  the  order  of  the  Zodiac,  and  is 
situated  south  of  the  Dolphin,  and  next  east  of 
Sagittarius.  Its  mean  declination  is  20°  south, 
and  its  mean  right  ascension,  310°.  It  is  therefore 
on  the  meridian  about  the  18th  of  September.  It 
is  to  be  observed  that  the  first  point  of  the  sign 
Capricorn,  not  the  constellation,  marks  the  southern 
tropic,  or  winter  solstice.  The  sun,  therefore, 
arrives  at  this  point  of  its  orbit  the  21st  of  Decem- 
ber, but  does  not  reach  the  constellation  of  Capricorn 
until  the  16th  of  January. 

The  sun  having  now  attained  its  utmost  declina- 
tion south,  after  remaining  a  few  days  apparently 
stationary,  begins  once  more  to  retrace  its  progress 
northwardly,  affording  to  the  wintry  latitudes  of 
the  north,  a  grateful  presage  of  returning  spring. 

At  the  period  of  the  winter  solstice,  the  sun  is 
vertical  to  the  tropic  of  Capricorn,  and  the  south- 
ern hemisphere  enjoys  the  same  light  and  heat 
which  the  northern  hemisphere  enjoys  on  the  21st 
of  June,  when  the  sun  is  vertical  to  the  tropic  of 
Cancer.  It  is  at  this  period,  mid  day  at  the  south 
pole,  and  midnight  at  the  north  pole. 

The  whole  number  of  stars  in  this  constellation 
is  fifty  one  ;  none  of  which  are  very  conspicuous. 
The  ,three  largest  are  only  of  the  3d  magnitude. 
There  is  an  equal  number  of  the  4th. 


CONSTELLATION  OF  CAPRICORNUS. 

The  head  of  Capricorn  may  be  recognized  by 
means  of  two  stars  of  the  3d  magnitude,  situated 
a  little  more  than  2°  apart,  called  Giedi,  marked  a, 
and  Dabih,  marked  /3.  They  are  28°  from  the  Dol- 
phin, in  a  southerly  direction. 

Giedi  is  the  most  northern  star  of  the  two,  and 
is  double.  If  a  line  be  drawn  from  Lyra  through 
Altair,  and  produced  about  23°  farther,  it  will  point 
out  the  head  of  Capricorn.  These  two  stars  come 
to  the  meridian  the  9th  of  September,  a  few  minutes 
after  Sad'r,  in  Cygnus. 

A  few  other  stars,  of  inferior  note,  may  be  traced 
out  by  reference  to  the  maps. 

The  sign  of  the  Goat  was  called  by  the  ancient 
orientalists  the  "  Southern  Gate  of  the  Sun,"  as 
Cancer  was  denominated  the  "  Northern  gate." 
The  ten  stars  in  the  sign  Capricorn,  known  to  the 
ancients  by  the  name  of  the  "  Tower  of  Gad,"  are 
probably  now  in  the  constellation  Aquarius. 

TELESCOPIC    OBJECTS. 

ata  CAPHICORISI.— A.  R.  20  h.  09  m.  10  s.  Dec.  =  —  13°  02'  01". 
A  double  star  of  special  interest.  A  3,  B  16,  magnitude. 

This  minute  point  of  light  was  regarded  by  Sir  John  Herschel  as 
possibly  a  satellite,  and  shining  by  a  reflected  light.  On  a  cursory 
review  of  this  region  of  the  heavens,  in  September,  1846,  I  turned  the 
instrument  on  aa  Capricorn!  in  the  presence  of  nearly  a  full  moon,  and 
instantly  detected  the  small  companion.  I  had  forgotten  that  this  was 
one  of  the  stars  to  which  Herschel  had  directed  attention,  and  supposed 
that  1  might  be  the  first  who  had  seen  the  companion.  A  slight  reference 
to  the  catalogues  showed  this  to  be  wrong.  It  does  not  appear  on 
Striive's  great  catalogue,  neither  do  I  find  any  measures,  except  a  few  of 
position  by  Sir  John  Herschel,  in  Sept.  26thr  1832. 

Pos.    141°  42'         No  distance  given. 

I  measured  this  object  in   August  and  September,   1846,  and  found 

Pos.  1440  H'         Dis.  6".36 

This  star  is  really  quintupk,  the  most  distant  star  of  the  five  being 
373"  from  the  principal.  t 

p  CAPHICORNI.— A.  R.  =  20  h.  19  m.  44  s.     Dec.  =  —  18°  20' 
02".     A   double   star  with  a  distant  companion.     A  5,  B  9,  C  7£,  mag. 
Pos.  A  B  1760  42'        Dis.  3".8         Epoch  1830.73     Smyth. 
176     56  3  .094  1847.70     Mitchel. 

This  object  is  found  on  the  right  ear  of  Capricorn. 


196 


GEOGRAPHY  OF  THE  HEAVENS. 


o  2  CAPHTCORNI.— A.  R.  =  20  h.  20  m.  43  s.  Dec.  =  —  1QO  06' 
04".  A  double  star  between  the  right  ear  and  the  eye  of  the  aniiaaL 
A  6,  B  7,  magnitude. 

Pos.  239°  09'         Dis.  21  ".8         Epoch  1832.59     Smyth. 

The  connexion  is  merely  optical,  as  seems  to  be  shown  by  the  recorded 
measures. 

A  GLOIIULAR  CLUSTER. — A.  R.  =  20  h.  44  m.  39  s.  Dec.  =  — 
13°  07'  06".  Between  Aquarius  and  the  neck  of  Capricorn,  due  east 
of  «t  Capricorni. 

Discovered  by  Messier  in  1 780.  , 

Resolved  by  Herschel,  and  pronounced  to  be  in  the  243d  order  of 
distances,  and  described  by  him  as  follows.  "  It  is  a  cluster  of  stars  of 
a  round  figure,  but  the  very  faint  stars  on  the  outside  of  globular  clusters 
are  generally  a  little  dispersed,  so  as  to  deviate  from  a  perfectly  circular 

form There  are  many  stars  in  the  same  field  of  view,  but 

they  are  of  several  magnitudes,  totally  different  from  the  excessively 
small  ones  which  compose  the  cluster.  It  is  not  possible  to  form  an 
idea  of  the  number  of  stars  which  form  such  a  cluster,  but  we  are  not 
to  estimate  them  by  hundreds." 

A  FINE  CLUSTER — A.  R.  =  21  h.  31  m.  16  s.  Dec.  =  —  23° 
52'  04".  Under  the  caudal  fin  of  the  animal. 

Discovered  by  Messier  in  1764,  who  saw  it  circular,  and  without 
any  star. 

Resolved  by  Sir  William  Herschel  in  1783.  Examined  by  myself  in 
September,  1 847,  and  described  as  follows.  An  irregular  cluster.  It 
brightens  at  the  center,  and  throws  out  three  distinct  radiations  of  stars. 
All  are  directed  downwards,  or  towards  the  north.  An  8th  magnitude 
star  precedes  the  cluster  by  about  5  minutes  of  arc.  Several  stars  are 
in  the  field. 


In  closing  our  review  of  the  constellations,  we 
present  the  following  table,  exhibiting,  for  each 
month  in  the  year,  the  rising,  culminating,  and  set- 
ting of  the  visible  constellations. 


Rising. 
Hercules, 
Corona  Borealis, 
Bootes, 
Virgo, 
Crater, 
Pyxis  Nautica, 
Argo  Navis. 

JANUARY. 

Cui/tiiriatittg. 
Draco, 
Polaris, 
Camelopardus, 
Lynx, 
Gemini, 
Monoceros, 
Canis  Major. 

Setting. 
Cygnus,  tfie  neck, 
Pegasus,  the  hoofs, 
Pisces,  the  ribbon, 
Cetus,  the  body, 
Eridanus, 
Columba  Noachi. 

TABLE  OF  CONSTELLATIONS. 


197 


FEBRUARY. 

Riaing. 

Culminating. 

Setting. 

Lyra, 

Cygnus,  the  tail, 

Pisces,  the  N.  fish, 

Hercules,  —  shoulders, 

Cepheus,  the  knee, 

Aries,  the  fore  legs, 

Serpens,  the  head, 

Polaris, 

Cetus,  the  head, 

Virgo,  the  feet, 

Ursa  Major,  fore  legs, 

Eridanus, 

Corvus, 

Lynx,  the  tail, 

Lepus,  the  fore  legs, 

Hydra,  the  lower  fold. 

Cancer,  the  claws, 

Canis  Maj  .  ,  hind  legs 

Hydra,  the  head. 

Argo  Navis. 

MARCH. 

4< 

Cygnus,—foll'g  wing 
Lyra, 

Lacerta,  the  back, 
Cepheus,  the  arm, 

Andromeda,  the  body, 
Triangulum, 

Hercules,  the  head, 

Polaris, 

Musca, 

Ophiuchus,  the  head, 

Ursa  Major,  hind  legs 

Taurus, 

Serpens,  the  middle, 

Leo,  thefiank, 

Orion, 

Libra, 

Crater, 

Canis  Maj.,  the  head. 

Hydra,  the  tail 

Hydra,  the  body. 

APRIL. 

Lacerta, 
Vulpecula, 

Andromeda,  the  body 
Cassiopeia,  the  waist 

Andromeda,  the  feet, 
Medusa's  Head, 

Sagitta, 

Polaris, 

Taurus,  the  horns, 

Aquila,  the  tail, 

Ursa  Major,  the  tail, 

Orion,  the  head, 

Ophiuchus,  the  knees, 

Canis   Venatici,    the 

Monoceros, 

fore  legs, 

Scorpio,  the  head, 

Vergo,  the  waist, 

Pyxis  Nautica, 

Centaurus,  the  head. 

Corvus,  the  tail. 

Antlia  Pneumatica. 

MAY. 

Andromeda,  the  feet, 

Perseus,  the  head, 

Auriga,  the  tegs, 

Pega.sus,  the  fore  kgs, 

Cassiopeia,  the  feet, 

Gemini,  the  legs, 

Equulus,  the  nose, 

Polaris, 

Cancer, 

Delphinus,^  body, 

Draco,  the  tail, 

Hydra,  the  heart, 

Antinous, 

Bootes,  the  body, 

Crater, 

Scorpio,  the  tail, 

Libra, 

Corvus, 

Lupus,  ike  head,     /i 

Centaurus,  the  hand. 

Centaurus,  the  head. 

JUNE. 

Medusa's  Head, 

Auriga,  the  kids, 

Gemini,  the  head, 

Triangulum, 

Camelopardus, 

Cancer,  the  body, 

Pisces,  the  N.  fish, 

Polaris, 

Leo,  the  fore  legs, 

Pegasus,  the  wing, 

Draco,  the  body, 

Sex.  Uraniae, 

Aquarius,  shoulders, 

Hercules,  the  back, 

dorvus, 

Capricornus,  the  head, 

Ophiuchus, 

Hydra,  the  tail, 

Sagittarius,  the  body. 

Scorpio,  the  tail. 

Lupus,  the  head. 

R2 


198 


GEOGRAPHY  OF  THE  HEAVENS. 


JULY. 

Rising. 

Culminating. 

Setting 

Auriga,  ttie  waist., 

Lynx,  the  head, 

Lynx,  the  hind  legs, 

Perseus,  the  feet, 

Camelopardus,  neck, 

Leo  Minor,  the  kgst 

Musca, 

Polaris, 

Leo,  the  tail, 

Aries,  the  head, 

Draco, 

Virgo,  the  shoulders, 

Pisces,  the  tail, 

Lyra, 

Libra, 

Aquarius,  the  legs, 

Scutum  Sobieski, 

Scorpio,  the  body. 

Sagittarius,  the  hips. 

Sagittarius,  the  head. 

/ 

AUGUST. 

Lynx,  the  body, 

Ursa  Maj.,  the  head, 

Leo  Minor, 

Gemini,  Castor's  arm 

Polaris, 

Coma  Bernices, 

Auriga,  the  knees, 

Cepheus,  the  sceptre, 

Bootes,  the  feet, 

Taurus,  the  head, 

Cygnus,  the  body, 

Libra, 

Cetus,  the  mouth, 

Vulpecula, 

Serpentarius,  —  leg** 

Pisces  Australis, 

Delphinus, 

Sagittarius,  the  waist* 

Microscopium. 

Capricornus,  neck. 

SEPTEMBER. 

Leo  Minor,  the  head, 

Ursa  Major,  the  body, 

Canes  Venatici, 

Lynx,  the  hind  legs, 

Draco,  the  tail, 

Bootes,  the  knees, 

Gemini,  the  bodies, 

Polaris, 

Serpens,  the  head, 

Orion,  the  shoulders, 

Cepheus,  head  <$-  body 

Ophiuctfus,  the  waist, 

Eridanus, 

Pegasus,  the  chest, 

Scutum  Sobieski, 

Cetus,  the  legs, 

Aquarius, 

Sagittarius, 

App.  Sculptoris. 

Piscis  Australis. 

Piscis  Australis. 

OCTOBER. 

Leo  Minor,  the  body, 

Ursa  Major,  the  tail, 

Bootes,  the  shoulders, 

Cancer,  the  body, 

Draco,  the  tail, 

Corona  Borealis, 

Canis  Minor,  —  head, 

Polaris, 

Hercules,  shoulders, 

Monoceros,  the  neck, 

Cassiopeia,  the  head, 

Ophiuchus,  the  head, 

Orion,  the  kgj 

Andromeda,  breast, 

Taurus  Poniatowski, 

Lepus,  the  head, 

Pisces,  the  ribbon, 

Capricornus,  the  head 

Fornax  Chemica. 

Cetus,  the  tati. 

Piscis  Australis. 

NOVEMBER. 

Canes  Venatici, 

Draco,  the  last  coil, 

Hercules,  the  legs, 

Leo,  the  body, 

Ursa  Minor,  the  head, 

Cerberus,  et  Ramus. 

Hydra,  the  head, 

Polaris, 

Sagitta, 

Monoceros, 

Perseus,  shoulders, 

Aquila,  the  body, 

Canis  Major,  —  head, 

Aries,  the  body 

Equulusf 

Lepus,  body, 

Cetus,  the  mouth, 

Aquarius, 

Eridanus. 

Fornax  Chemica. 

App.  Sculptoris. 

TABLE    OF    CONSTELLATIONS. 

DECEMBER. 


199 


Rising. 
Bootes, 

Coma  Bernices, 
Leo, 

Sextans  Uraniae, 
Hydra, 
Argo  Navis, 
Canis  Major. 


Culminating. 
Draco,  the  middle, 
Ursa  Minor,  haunch, 
Polaris, 

Camelopardus,  body, 
Taurus,  the  head. 
Eridanus. 


Setting. 
Lyra, 

Cygnus,  the  head, 
Vulpecula,  the  legs, 
Pegasus,  the  head, 
Pisces,  the  W.Jish, 
Cetus,  the  tail, 
Fornax  Chemica. 


N.  B.  The  risings  are  taken  along  the  horizon, 
from  the  north,  round  by  the  east,  to  the  south  ; 
the  culminations  from  the  north  horizon,  over  the 
pole  and  zenith,  and  thence  down  to  the  south  hori- 
zon ;  the  settings  are  reckoned  from  the  north,  by 
the  west,  round  to  the  south.  Polaris,  though  not 
always  precisely  on  the  meridian,  is  included  in 
every  month  as  a  guide. 


THE   FIXED   STARS.  201 


;    CHAPTER  V. 

THE    FIXED    STARS  — THEIR    DISTANCE    AND    MOTIONS  —  THE 
MILKY    WAY  —  CLUSTERS  —  NEBULJE. 

THUS  far  in  our  examination  of  the  constellations,  the  stars 
have  only  been  considered  in  their  relations  of  apparent  magni- 
tude or  brilliancy  and  position.  Their  absolute  magnitudes, 
distances,  motions,  and  positions,  have  not  been  regarded,  except 
as  notices  have  been  taken  of  a  few  among  the  telescopic  objects. 
We  propose  to  consider,  now,  the  discoveries  which  have 
recently  been  made  in  sidereal  astronomy ;  and  we  commence 
with  the  parallax  of  the  fixed  stars. 

DEFINITION. — The  parallax  of  any  heavenly  body  is  the  ap- 
parent change  in  its  position,  occasioned  by  any  real  change  in 
the  position  of  the  spectator. 

Thus,  if  a  person  on  the  earth's  surface  should,  while  looking  at 
the  moon  just  rising,  be  suddenly  transported  down  to  the  earth's 
center,  as  he  descended  the  moon  would  appear  to  ascend,  and 
this  seeming  change  in  the  moon's  place  is  a  paralladic  change. 
The  rapid  apparent  whirling  of  the  forest  trees,  occasioned  by  fly- 
ing swiftly  past  them  in  a  coach  or  car,  is  a  similar  effect  from  a 
like  cause.  More  accurately,  the  moon's  parallax  is  the  angle 
formed  at  the  moon's  center  by  two  lines,  the  one  drawn  tangent 
to  the  earth's  surface,  the  other  drawn  to  the  earth's  center.  In 
case  a  spectator  could  be  transported  to  the  moon's  center,  at  the 
instant  she  is  rising  above  the  horizon  of  any  place,  and  could 
see  the  earth's  radius  drawn  to  this  place,  the  two  visual  rays 
drawn  to  the  extremities  of  this  radius  would  form  an  angle  at 
the  eye  of  the  observer,  which  would  be  the  moon's  horizontal 
parallax.  These  two  visual  rays  and  the  earth's  radius  form  a 
triangle,  in  which  one  side  (the  earth's  radius)  is  known,  the 
angles  are  readily  measured,  and  hence  it  becomes  possible  to 
learn  the  value  of  the  remaining  sides,  either  of  which  measures 
the  moon's  distance  from  the  earth. 

When,  therefore,  the  parallax  of  any  heavenly  body  is  once 
determined,  it  is  an  easy  matter  to  compute  its  distance.  If  one 
could  be  transported  to  a  fixed  star,  when  rising,  and  view  from 
this  position  the  earth's  radius,  the  angle  formed  by  the  visual 
rays  drawn  to  the  two  extremities  of  this  radius,  would  be  the 
star's  parallax.  In  consequence  of  the  vast  distance  of  the  fixed 
stars,  this  angle,  thus  formed,  is  too  minute  to  be  appreciable  ; 
no  instruments  devised  by  human  skill  or  science,  can  be  con- 


202  GEOGRAPHY  OF   THE   HEAVENS. 

structed  so  as  to  measure  so  minute  a  quantity.  We  are,  there- 
fore, obliged  to  resort  to  some  other  method  to  determine  the 
parallax  of  the  stars.  In  case  the  earih  were  at  rest  in  the 
universe,  there  would  be  no  possibility  of  ever  measuring  the 
distance  of  the  fixed  stars;  but  its  annual  sweep  around  the  sun 
in  an  orbit  whose  radius  is  about  ninety-five  millions  of  miles, 
transports  the  astronomer  through  space,  around  an  orbit  whose 
longest  diameter  is  nearly  two  hundred  millions  of  miles.  If, 
now,  the  observer  send  up  a  visual  ray  to  a  fixed  star,  when 
at  one  extremity  of  the  longest  diameter  of  the  earth's  orbit,  and 
at  the  end  of  six  months,  when  he  shall  have  reached  the  other 
extremity  of  the  same  diameter,  he  send  up  a  second  visual  ray 
to  the  same  star,  these  two  rays  will  stand  upon  a  base  whose 
length  is  nearly  two  hundred  millions  of  miles,  and  the  angle 
formed  by  them,  at  the  fixed  star,  will  be  its  parallax.  To 
render  this  plainer,  suppose  a  globe  bright  as  the  sun,  and  of  a 
diameter  equal  to  that  of  the  earth's  orbit,  filled  this  grand  cir- 
cumference; the  apparent  diameter  of  such  a  globe,  as  seen 
from  the  star  in' question,  would  be  its  parallax. 

At  first  view  it  would  seem  almost  impossible  to  remove  a 
spectator  so  far,  that  a  globe  of  two  hundred  millions  of  miles 
in  diameter  should  shrink  to  a  point  almost  imperceptible,  or  that 
by  distance  its  diameter  should  become  scarcely  perceptible  with 
the  most  powerful  instruments;  yet  this  is  literally  true.  To 
measure  this  apparent  diameter,  or  to  obtain  the  angle  of  the  visual 
rays  drawn  from  its  extremities  to  a  fixed  star,  has  for  more  than  a 
hundred  years,  called  into  requisition  the  highest  skill,  genius, 
and  patience,  ever  put  forth  by  man.  The  problem  is  no  less  than 
the  determination  of  the  distances  of  the  fixed  stars.  Three  pro- 
cesses have  been  employed  in  the  investigation  of  this  problem, 
each  of  which,  and  its  results,  we  shall  succinctly  present. 

1.  BRADLEY'S  METHOD. — Suppose  a  telescope  bolted  firmly  to 
a  solid  rock,  hewn  in  the  form  of  a  vertical  shaft.  This  rock 
is  absolutely  immovable,  and  the  telescope  is  so  situated  that 
its  axis  is  exactly  vertical,  and  is  perfectly  immovable.  In  the 
focus  of  the  eye  piece  of  the  telescope,  let  two  spider's  webs  of 
the  finest  texture  cross  each  other  at  right  angles,  and  by  their 
intersection  form  a  point  of  almost  mathematical  minuteness, 
precisely  in  the  axis  of  the  telescope.  With  this  instrument  the 
astronomer  is  prepared  to  commence  his  research  of  the  parallax 
of  a  fixed  star.  Placing  his  eye  to  the  instrument,  he  watches 
until  a  certain  fixed  star  enters  the  field  of  the  telescope.  It 
actually  threads  like  a  bead  of  light,  the  spider's  line  drawn 
parallel  to  the  direction  of  the  star's  apparent  diurnal  motion  ;  it 
moves  on,  and  the  precise  instant  when  it  reaches  the  intersection 
of  the  spider's  lines  is  noted  and  recorded,  and  thus  the  first 
observation  is  terminated.  Now  the  telescope,  its  rocky  base. 


THE   FIXED   STARS.  203 

and  the  observer,  are  carried  by  the  earth  round  the  sun,  and  in 
case  any  change  in  the  apparent  place  of  the  star  is  occasioned 
by  the  revolution  of  the  earth  in  its  orbit,  as  the  star  is  watched 
night  after  night,  throughout  the  year,  it  will  be  found  slowly 
to  leave  the  spider's  line  which  it  at  first  threaded,  and  gradu- 
ally to  move  either  towards  the  north  or  south,  while  it  fails  to 
cross  the  center  at  the  exact  instant  of  time  first  recorded.  A 
little  thought  will  render  clear  this  beautiful  and  simple  method 
of  ascertaining  the  parallax,  or  apparent  change  of  place,  of  the 
fixed  stars.  Such  was  mainly  the  method  employed  by  Bradley, 
the  great  English  astronomer.  Its  accuracy  was  wonderful,  but 
it  failed  to  detect  any  parallax.  Buried  in  depths  almost  infinite, 
the  stars  escaped  from  this  first  scrutinizing  process. 

2.  HERSCHEL'S  METHOD. — In  the  outset  of  Herschel's  explora- 
tions among  the  double  stars,  he  believed  them  to  be  only 
optically  related  ;  that  is,  their  proximity  was  occasioned  by 
the  fact  that  the  visual  ray  drawn  by  the  observer  to  one  star, 
passed  almost  exactly  through  the  other.  In  case  then,  two 
stars  could  be  found  very  near  to  each  other,  of  whose  compo- 
nents the  one  was  about  double  the  other,  it  was  fair  to  conclude 
that  the  smaller  was  twice  as  remote  as  the  larger,  and  jf 
properly  chosen,  the  annual  revolution  of  the  earth  in  its  orbit 
could  hardly  fail  to  cause  some  change  in  the  relative  positions 
of  these  stars.  Suppose  that  on  the  first  of  January  the  small 
star  is  seen  exactly  on  the  right  of  the  large  one;  at  the  end  of 
three  months  it  is  seen  a  little  to  the  south  and  just  under  the 
large  one;  at  the  close  of  six  months  it  is  to  the  left;  at 
the  end  of  nine  months  it  is  just  above  and  a  little  north  of  the 
large  star;  and  when  the  year  closes  it  comes  to  resume  its 
primitive  position.  In  case  such  changes  are  repeated  from 
year  to  year,  and  in  the  same  order,  and  in  many  double  stars, 
it  is  impossible  to  resist  the  conclusion  that  it  is  a  parallactic 
change.  Such  was  the  method  practised  by  Herschel,  but  an 
unforeseen  discovery  destroyed  the  hope  of  detecting  the  parallax 
in  this  way.  It  was  found  that  these  double  stars,  in  many 
instances  at  least,  were  not  merely  related  by  accidental  position, 
but  were  actually  united  by  the  great  law  of  universal  gravita- 
tion ;  one  star  or  sun  revolving  about  the  other,  or  rather  the  two 
suns  revolving  about  their  common  center  of  gravity.  The  actual 
motions  became,  in  this  way,  so  involved  in  these  only  apparent  or 
parallactic  motions,  that  to  distinguish  them  became  impossible. 

These  methods  then  failed  to  reveal  the  distances  of  the  stars, 
although  they  were  not  without  results  of  the  most  important 
character,  and  without  a  knowledge  of  which,  the  problem  of  the 
parallax  could  never  have  been  resolved.  Bradley  discovered  the 
nutation  and  aberration  of  the  fixed  stars,  while  Herschel  reached 
the  grand  fact  of  the  binary  character  of  the  double  stars. 


204  GEOGRAPHY    OF   THii    HEAVENS. 

3.  BESSKL'S  METHOD. — After  mounting  a  large  telescope  call- 
ed a  hetiometer,  peculiarly  adapted  for  the  micrornetrical  measure 
of  large  as  well  as  minute  distances  among  the  double  stars, 
Bessel  selected  61  Cygni  as  the  object  on  which  he  determined 
to  concentrate  his  entire  attention.  This  double  star  was  eligi- 
bly situated  in  the  heavens,  and  could  be  observed  nearly  every 
mo.nth  in  the  year.  It  had  near  it  several  minute  stars  which 
could  be  used  as  points  of  reference,  and  finally  the  rapidity  of 
its  proper  motion  indicated  its  probable  nearness  to  our  sun  and 
system.  Bessel  selected  two  minute  stars  as  points  of  reference, 
the  one  in  a  line  nearly  perpendicular  to  the  middle  point  of  the 
line  joining  the  components  of  61  Cygni,  the  other  in  the  direc- 
tion of  this  line.  With  the  heliometer  he  measured  the  distance 
of  the  middle  point  of  the  line  joining  the  components  of  61 
Cygni,  from  each  of  the  points  of  reference,  16  times  each  night, 
and  finally  detected  a  change  in  these  distances  which  seemed 
to  depend  on  the  orbitual  revolution  of  the  earth.  Some  three 
years  of  observation  confirmed  the  accuracy  of  the  first  results, 
and  gave  the  parallax  of  this  double  star  equal  to  0".3480,  or  only 
about  three-tenths  of  one  second  of  arc,  so  that  if  a  globe  of 
100,000,000  of  miles  in  diameter,  could  be  seen  from  this  fixed 
star,  its  diameter  would  not  appear  greater  than  about  the  six- 
thousandth  part  of  the  sun's  apparent  diameter.  The  parallax 
once  obtained,  the  distance  is  readily  deduced,  and  is  found  to  be 
657,700  times  greater  than  the  earth's  distance  from  the  sun,  or 
so  remote  that  the  light  of  the  star  only  reaches  us  after  a  jour- 
ney of  more  than  ten  years,  although  it  flies  at  the  rate  of  twelve 
millions  of  miles  in  every  minute. 

The  distance  of  the  double  star  being  known,  observation 
gives  us  about  540  years  for  the  period  in  which  the  components 
revolve  around  their  common  center  of  gravity  in  an  orbit  whose 
diameter  is  about  ninety  times  the  diameter  of  the  earth's  orbit, 
while  the  amount  of  matter  in  these  two  stars  is  a  little  less  than 
half  that  contained  in  our  sun. 

Since  Bessel  determined  the  parallax  of  61  Cygni,  other 
astronomers  have  pursued  the  investigation  with  success.  The 
following  have  been  deduced  by  the  Russian  astronomer  M. 
Peters,  and  announded  in  a  recent  work  by  M.  Striive,  of 
Pulkova. 

Absolute  parallax  of  61  Cygni  +  00".349. 

"  "  *  Lyra?  -f  00  .103. 

««     ,         "  Polaris  -f  00  .067. 

"  "  Groombridge  No.  1830  -f-  00  .226. 

"  "  *  Aurigae  or  Copella      -|-  00  .046, 


Ursa  Major  -f-  00  .133. 

a.  Botitis,  Arcturis          -4-  00   .127. 


THK  FIXED  STARS.  205 

From  the  table  it  is  readily  seen  that  61  Cygni  is  the  nearest 
of  all  the  fixed  stars  whose  distances  have  been  discovered. 

M.  Striive,  by  a  beautiful  train  of  reasoning,  deduces  the  rela- 
tive distances  of  the  stars  of  the  various  magnitudes,  from  the 
1st  to  the  6th  magnitude  inclusive,  and  finds  them  to  constitute 
a  geometrical  progression  whose  common  ratio  is  1  divided  by 
the  square  root  of  2.  Calling  the  distance  of  the  6th  magni- 
tude stars  10  000  he  finds 


Magnitude.  Dist.  determined. 

6  1.0000  1  0000. 

5  0.6998  0.7071. 

4  0.5001  0.5000. 

3  0.3602  0.3536. 

2  0.2413  0.2500. 

1  0.1424  0.1768. 

It  will  be  seen  that  the  numbers  in  the  two  columns  scarcely 
differ,  except  in  the  case  of  stars  of  the  1st  magnitude,  and  here 
too  few  exist  to  furnish  M.  Striive  with  the  requisite  data  for 
his  computations.  So  that  this  most  curious  law  of  distances 
would  seem  to  be  founded  in  nature.  Every  even  term  is  half 
the  preceding  even  one,  and  the  same  of  every  odd  term. 

If  it  were  now  possible  to  determine  the  absolute  mean 
distance  of  the  stars  of  any  one  magnitude,  the  real  distances 
of  all  other  magnitudes  would  readily  be  derived  from  this 
remarkable  law.  This  has  been  approximately  accomplished 
by  the  Russian  astronomers.  From  the  actual  parallax  of  about 
thirty  stars  of  the  2d  magnitude,  the  value  of  the  mean  parallax 
of  all  the  stars  of  that  magnitude  has  been  derivecT,  and  we 
are  now  able  to  present  the  following  table: 


App.  mag. 

1  Distance  (radius  of  )          (  Time  for  light  to 
Parallax.       /Earth's    orbit  =1).  S          I'^um*  jit  wirs 

1 

00' 

'.166 

1,216.000 

19.6 

2 

00 

.098 

2,111.000 

33.3 

3 

00 

.065 

3,151.000 

49.7 

4 

00 

.047 

4,375.000 

69.0 

5 

00 

.034 

6,121.000 

96.6 

6 

00 

.024 

8,746.000 

137.9 

7 

00 

.014 

14,230.000 

224.5 

8 

00 

.008 

24,490.000 

386.3 

9 

00 

.006 

37,200.000 

5865 

Herschel's 
smallest  stars 

Joo 

.00092 

224,500.000 

3541.0 

It  is  not  pretended  that  these  results  are  absolute.     These 
values  are  only  approximate,  but  the  errors  are  comparatively 
small;   and  show  to  us  clearly,  the  vastness  of  the  universe 
of  God. 
S 


206  GEOGRAPHY   OF   THE   HEAVENS. 

Having  learned  in  this  way  the  distances  cf  the  fixed  stars, 
the  inquiry  arises,  how  are  these  objects  distributed  throughout 
space?  Are  they  scattered  indifferently  in  all  directions,  and  at 
distances  nearly  equal  from  each  other,  or  is  their  distribution 
governed  by  any  attainable  law?  The  bright  circle  of  light 
called  the  Milky  Way^  which  sweeps  round  the  entire  circuit  of 
the  heavens,  and  which  to  the  naked  eye  appears  only  faintly 
luminous,  when  examined  with  the  telescope,  is  found  to  consist 
of  millions  of  stars,  crowded  and  condensed  together  with  the 
most  extraordinary  richness  and  profusion.  Herschel  conceived 
the  idea  of  measuring  the  depths  to  which  the  stars  extended  in 
the  Milky  Way,  and  by  reaching  out  beyond  its  extreme  limits, 
ascertaining  the  figure  which  would  be  formed  by  cutting  this 
vast  bed  of  stars  by  a  plane  drawn  perpendicularly  to  its  surface. 
It  is  manifest,  that  if  the  stars  are  all  at  equal  distances,  and 
finite  in  number,  that  wherever  the  stratum  extends  deepest 
into  space,  there  will  we  be  enabled  to  count  the  greatest 
number  of  stars  in  the  field  of  a  given  telescope.  And  indeed, 
the  number  counted  in  any  two  directions,  by  the  same  telescope, 
will  give  the  relative  depth  to  which  the  stars  extend  at  these 
two  points.  Such  was  Herschel's  plan  of  sounding  the  Milky 
Way,  and  of  learning  its  figure.  With  the  full  power  of  his 
twenty  feet  reflecting  telescope,  he  thought  it  possible  to  pierce 
through  even  the  deepest  portions  of  the  Milky  Way,  and  to 
send  the  visual  ray  far  beyond.  This  idea,  so  long  maintained 
by  the  followers  of  Herschel,  has  recently  been  attacked  by 
Prof.  Striive  of  Pulkova,  who  maintains  that  it  was  abandoned 
by  Herschel  himself  in  his  later  papers.  Sir  John  Herschel 
does  not  accord  with  the  views  of  Striive,  but  maintains  the 
original  opinions  of  his  father. 

From  the  investigations  of  the  two  Herschels,  the  vast  stra- 
tum of  stars,  called  the  Milky  Way,  appears  to  be  arranged 
under  the  figure  of  a  flat  ring,  whose  thickness  is  small  when 
compared  with  its  diameter.  The  central  parts  of  the  ring  are 
not  so  thickly  strewn  with  stars  as  the  outer  portions  or  circum- 
ference. The  rim  is  divided  into  two  branches,  or  streams  of 
stars,  which  diverge  from  each  other  for  a  certain  distance,  but 
finally  re-unite  and  flow  on  together.  The  two  Herschels  have 
made  a  sufficient  number  of  observations  to  determine  the  figure 
cut  from  this  bed  of  stars  by  a  plane  perpendicular  to  its  surface, 
and  cutting  across  the  portion  where  the  two  streams  are  most 
distant  from  each  other.  There  are  portions  of  the  Milky  Way 
included  in  this  section,  in  which  it  is  said,  the  stars  extend  so 
deep  in  space  that  the  series  in  a  right  line,  from  the  sun  out  to 
the  extreme  limit,  cannot  number  less  than  five  hundred  stars, 
each  as  remote  from  the  other  as  61  Cygni  is  from  our  sun.  ID 
case  we  admit  this  statement,  there  are  stars  belonging  to  oui 


THE  MILKY   WAY.  207 

Milky  Way  so  widely  separated,  that  their  light  will  require 
more  than  ten  thousand  years  to  pass  from  one  to  the  other,  or 
to  sweep  across  the  longest  diameter  of  this  mighty  universe 
of  stars. 

If  Striive's  idea  of  the  absolute  unfathomable  character  of  the 
Milky  Way  be  adopted,  it  only  increases  the  sweep  or  range  of 
suns  and  systems,  grouping  them  into  subordinate  clusterings, 
and  uniting  them  into  one  unbounded,  immeasurable,  ^numer- 
able, whole.  In  whatever  way,  under  whatever  aspect,  we 
contemplate  this  vast  constellation  of  constellations ;  this  mag- 
nificent cluster  of  clusters  ;  the  number,  distance,  magnitude,  and 
brilliancy,  of  its  components,  cannot  fail  to  fill  the  mind  with 
wonder  and  astonishment. 

Admitting  that  the  telescopic  vision  sweeps  beyond  the  limits 
of  the  Milky  Way,  it  may  be  asked,  what  does  the  eye  encounter 
in  these  remote  regions  ?  Many  objects  lying  in  these  far  distant 
portions  of  space,  have  already  been  noticed  among  the  tele- 
scopic objects  of  the  different  constellations.  These  are  the 
clusters  and  nebulas.  By  a  careful  examination  of  these  wonder- 
ful objects,  Herschel  finally  reached  the  conclusion,  that  all  the 
clusters^  and  many  of  the  nebulae,  were  immense  aggregations 
of  stars,  forming  separate  universes,  as  extensive  and  rich  as  the 
Milky  Way  itself.  He  even  ventured  to  attempt  the  measure  of 
the  relative  depths  of  these  remote  objects.  His  method  is 
simple,  and  may  be  readily  comprehended.  The  naked  eye  can 
discern  stars  of  the  sixth  magnitude,  or  those  twelve  times  as 
remote  as  Sirius,  the  largest  and  brightest  star  in  the  heavens. 
In  case  the  pupil  of  the  eye  could  be  expanded  to  twice  its  present 
dimensions,  it  could  then  penetrate  twice  as  deep  into  space  as 
it  now  can,  or  would  see  Sirius  if  it  were  removed  backward 
twenty-four  times  deeper  into  space.  Now,  although  the  pupil 
of  the  eye  cannot  literally  be  expanded  to  twice  or  thrice  its 
present  size,  the  telescope  comes  in  to  accomplish  precisely  the 
same  effects ;  and  admitting  that  an  object  glass  permits  all  the 
light  which  falls  on  it  to  pass  through,  its  power  to  penetrate  space 
will  be  in  the  ratio  of  its  surface  to  that  of  the  pupil  of  the  human 
eye.  By  covering  a  large  object  glass  with  circular  coverings, 
pierced  with  apertures  of  one  inch,  two  inches,  &c.,  diameter  in 
the  center,  we  may  give  to  it,  at  pleasure,  different  space  penetra- 
ting powers.  Fixing  the  relation  of  these  to  the  eye,  we  are  pre- 
pared to  examine  any  object,  and  determine,  approximately,  its 
distance.  Suppose  a  nebula  is  seen  faintly  visible,  with  three 
inches  of  aperture  to  the  object  glass.  We  expand  the  aper- 
ture to  four  inches — it  appears  brighter,  but  no 'stars  are  seen. 
We  increase  the  aperture  to  five  inches,  the  nebula  grows  still 
brighter  at  the  center,  but  as  yet  no  point-like  stars  are  visible ; 
a  farther  increase  to  six  inches,  however,  shows  the  object  to 


208  GEOGRAPHY  OF  THE  HEAVENS. 

consist  of  millions  of  minute  stars,  just  rendered  visible  to  the 
eye.  Now  the  length  of  the  visual  ray  of  the  telescope,  com- 
pared with  that  of  the  unaided  eye,  is  readily  determined;  and 
knowing  this,  we  learn,  approximately,  the  distance  of  this 
cluster  of  stars.  In  this  way  Sir  W.  Herschel  determined  the 
profundity  of  all  the  principal  clusters. 

Some  of  the  nebulae  could  not,  by  any  space  penetrating  power 
of  his  great  telescopes,  be  resolved  into  stars.  Their  shapes 
were  irregular,  and  their  outlines  ill  defined.  Some  were 
easily  visible  to  the  naked  eye,  and  yet  no  telescopic  power 
could  resolve  them  into  stars.  Others  were  found  to  contain 
occasional  stars,  with  centers  of  more  or  less  condensed  light ; 
finally,  stars  were  found  surrounded  by  a  nebulous  haze  of  vast 
extent,  whose  center  was  occupied  by  the  star.  Examining  and 
comparing  all  these  phenomena,  Herschel  finally  reached  the 
conclusion,  that  while  vast  numbers  of  apparent  nebulae  were 
real  clusters  of  stars,  yet  there  were  some  in  which  the  material 
composing  them  was  a  kind  of  luminous  mist,  like  that  forming 
the  tails  of  comets.  He  conjectured  that  this  chaotic  matter 
might  possibly  furnish  the  material  out  of  which,  by  condensa- 
tion, stars  might  be  forming.  The  nebulous  stars,  as  well  as 
the  planetary  nebula,  seemed  to  accord  very  perfectly  with  this 
hypothesis.  Double  and  triple  nebulae  were  found,  from  which 
the  double  and  triple  stars  might  eventually  spring,  and  thus 
grew  up,  imperceptibly,  the  outlines  of  a  magnificent  theory,  a 
sort  of  sublime  cosmogony  of  the  universe.  These  speculations, 
enlarged  by  La  Place,  as  we  shall  see  hereafter,  were  made  to 
render  an  account  of  the  sun  and  planets,  and  the  peculiar 
arrangement  of  the  solar  system.  The  nebular  theory,  as  it  is 
termed,  had  for  a  long  while  its  ardent  supporters,  and  if  not 
absolutely  adopted  by  distinguished  astronomers,  at  least,  it  was 
received  by  them  with  no  inconsiderable  favor.  The  resolution 
of  the  nebula  in  Orion,  by  Lord  Rosse,  and  by  Prof.  Bond,  of 
Cambridge,  has  in  some  degree  shaken  the  faith  of  some  in  this 
remarkable  hypothesis,  while  it  is  justly  remarked,  that  Herschel 
only  adopted  it  after  the  resolution  of  hundreds  of  nebulae. 

In  case  we  abandon  the  idea  of  chaotic  matter  existing  in 
space,  and  adopt  the  notion  that  the  filmy,  almost  spiritual, 
objects,  which  barely  stain  with  light  the  blue  of  the  heavens, 
are  immense  congeries  of  stars,  it  only  expands  our  knowledge 
of  the  illimitable  extent  of  the  universe  of  God.  Some  of  these 
objects  are  so  remote,  that  a  hundred  thousand  years  must  roll 
away,  before  the  light  which  they  emit  could  traverse  the  dis- 
tance by  which  we  are  separated  from  them. 

Many  of  the  clusters  of  stars  appear  under  globular  forms,  and 
from  the  manifest  condensation  about  their  centers,  seem  to  in- 
dicate the  existence  of  some  active  energetic  power,  like  gravita- 


THE  MILKY   WAY.  209 

tion,  which  is  exerting  its  influence  on  the  individual  stars  of 
these  grand  systems.  The  extension  of  the  law  of  universal 
gravitation  to  the  region  of  the  fixed  stars,  was  long  believed, 
before  it  could  be  positively  demonstrated.  By  the  discovery  of 
the  binary  or  revolving  suns,  this  conjecture  became  a  positive 
fact.  In  a  large  number  of  instances,  the  orbits  described  by  these 
bodies  around  their  common  centers  of  gravity,  have  been  com- 
puted according  to  the  law  of  gravitation,  and  in  every  instance 
the  predictions  have  been  verified.  That  stars  do  attract  each 
other  is  now  positively  demonstrated,  and  the  law  of  attraction 
is  the  inverse  ratio  of  the  square  of  the  distance,  or  that  of  gravita- 
tion. If  two  or  three  stars,  grouped  together,  are  subject  to  this 
law,  it  is  reasonable  to  conclude  that  larger  collections,  such  as 
the  Pleiades,  or  Coma  Berenices,  may  be  under  the  controlling 
power  of  the  same  force.  And  if  this  be  true,  why  not  extend  its 
operation  to  the  mighty  cluster  of  clusters,  the  Milky  Way  itself. 

This  has  been  done  recently  by  M.  Madler,  of  Dorpat,  Russia, 
and  he  thi-nks  he  has  determined,  approximately,  the  center  of  the 
stratum  of  stars,  or  the  astral  system,  composing  the  Milky  Way. 
By  comparing  the  absolute  places  of  the  fixed  stars,  at  intervals 
of  one  or  two  hundred  years,  it  is  found  that  a  large  number  of 
them  are  in  motion,  and  with  an  appreciable  velocity.  This  is  • 
not  merely  apparent,  but  in  many  instances  must  be  absolute 
change  of  place  in  space.  Some  stars  are  moving  very  swiftly, 
and  exhibit  their  progressive  changes  in  a  few  months  ;  while 
others,  again,  move  with  such  extreme  slowness,  that  even 
hundreds  of  years  are  necessary  to  render  their  change  appre- 
ciable. It  seems  quite  as  reasonable  to  suppose  that  these  com- 
plex and  involved  motions  of  the  distant  stars,  should  be 
governed  by  some  simple  and  beautiful  law,  as  that  the  planets, 
whose  apparent  motions  were  far  more  complicated,  should  be 
reduced  to  order  and  simplicity.  This  great  task  of  unraveling 
the  complicated  phenomena  of  the  proper  motion  of  the  fixed 
stars,  has  been  attempted  by  the  Russian  astronomer. 

It  had  long  been  conjectured  that  the  analogy  existing  in  the 
solar  system  would  hold  among  the  systems  of  stars.  And  that 
as  the  sun  was  vastly  larger  than  his  revolving  planets,  and  as 
each  primary  planet  was  much  superior  to  his  revolving  moons, 
so  there  might  exist  in  space  some  mighty  central  sun,  whose 
vast  proportions  would  far  exceed  all  the  stars  subject  to  its  con- 
trolling influence.  This  analogy  was  broken  by  the  discovery 
of  the  binary  stars.  Here  we  find  many  instances  in  which  the 
components  are  exactly  equal  in  magnitude ;  others,  again  in 
which  the  one  is  slightly  superior  to  the  other ;  in  short,  all  possi- 
ble relations  of  magnitude.  This  does  not  interfere  with  the  sta- 
bility and  perfection  of  the  systems.  The  components  revolve 
about  their  common  center  of  gravity  as  though  it  were  filled 
s2 


210  GEOGRAPHY  OF  THE  HEAVENS. 

with  a  mass  of  solid  matter.  Madler  rejects  the  idea,  then,  of 
the  existence  of  any  vast  central  globe,  and  argues  thut  in  case 
it  existed,  it  would  be  impossible  to  prevent  its  discovery.  The 
stars  in  its  immediate  neighborhood  would  reveal  it  by  their  swift- 
er proper  motions ;  as  no  such  motions  are  known,  or  have  ever 
been  discovered,  it  is  fair  to  conclude  that  none  such  exist,  and 
that  there  is  no  central  predominant  orb,  but  a  mere  center  of 
gravity,  which  should  be  the  object  of  research.  By  a  train  of 
beautiful  and  ingenious  reasoning,  he  demonstrates  to  his  own 
satisfaction,  that  this  central  point  must  be  found  somewhere  in 
the  Milky  Way,  and  finally  locates  it  in  the  cluster  called  the 
Pleiades,  The  brightest  star  of  the  group  is  called  Alcyone  or 
»  Tauri,  and  the  star  at  present  occupies  the  center  of  gravity 
of  the.  grand  stratum  of  stars  composing  the  Milky  Way^  and 
around  this  center  all  the  millions  of  stars  are  slowly  performing 
their  vast  revolutions. 

Among  these  our  own  sun  and  system  is  comprehended,  and 
Madler  estimates  that  one  single  revolution  of  the  sun  around 
this  distant  center  requires  no  less  than  eighteen  millions  two  hun- 
dred thousand  years.  The  distance  of  Alcyone  from  our  sun 
cannot  be  less  than  thirty-four  millions  of  times  the  radius  of 
the  earth's  orbit.  Should  the  universe  endure  so  long,  at  the  end 
of  nine  or  ten  millions  of  years,  the  revolution  of  the  sun  in  its 
orbit  will  cause  a  total  change  in  the  apparent  relative  positions 
of  the  fixed  stars.  The  present  well  known  constellations  will 
have  been  swept  from  the  heavens,  and  new  configurations  of 
the  stars  will  have  usurped  the  places  of  the  old  ones.  No 
new  creation  will  cause  these  changes,  but  they  come  as  the  in- 
evitable consequences  of  the  motion  of  the  solar  system.  When 
we  shall  have  examined  the  construction  of  this  system,  we  shall 
then  present  the  evidences  of  its  swift  translation  through  space. 

It  seems  next  to  impossible  to  estimate  the  number  of  fixed 
stars  constituting  our  own  astral  system.  Catalogues  of  all  the 
brighter  stars  have  been  formed.  Some  of  these  contain  even  fifty 
thousand  stars,  observed  by  a  single  individual.  Striive  reaches 
the  conclusion,  that  Herschel's  twenty  feet  reflector  could  reach 
no  less  than  twenty  millions  three  hundred  and  seventy-four 
thousand  stars  in  the  celestial  sphere ;  and  it  has  been  estimated 
that  the  forty  feet  instrument  would  carry  the  number  up  to  at 
least  one  hundred  millions. 

Let  it  be  remembered  that  these  stars  compose  but  a  single 
astral  system,  or  as  the  Germans  term  them  "  Island  Universes." 
More  than  three  thousand  of  these  systems  have  been  discovered, 
some  of  them  doubtless  far  more  magnificent  and  populous  in 
stars  than  our  own ;  and  yet  all  these  innumerable  worlds  and 
suns  and  systems  have  been  brought  within  the  range  of  human 
vision  by  the  powers  of  the  telescope. 


THE  MILKY  WAY.  21 

The  power  of  this  instrument  in  penetrating  space  is  only 
equaled  by  its  extraordinary  capacity  to  divide  space.  The 
micrometer  of  the  great  refractors  now  in  use,  can  divide  a  single 
inch  into  eighty  thousand  equal  parts  !  and  should  two  close  fixed 
stars  commence  to  separate  from  each  other  hy  so  small  a  quan- 
tity that  even  three  millions  of  years  would  be  required  for  a 
complete  revolution  in  the  heavens,  these  delicate  instruments 
would  detect  the  motion  in  a  single  year.  With  such  instru- 
ments, it  is  not  wonderful  that  human  genius  dares  the  most  dif- 
ficult researches. 


212  GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTER    VI. 

GENERAL  PHENOMENA  OF  THE  SOLAR  SYSTEM. 

THUS  far  our  attention  has  been  directed  to  the  phenomena  of 
the  sidereal  heavens.  The  names,  positions,  and  relative  mag- 
nitudes of  the  stars;  their  changes  of  light,  proper  motion,  and 
physical  association  into  systems  of  greater  or  less  complexity, 
have  been  considered  and  explained.  The  mind  has  penetrated 
but  a  comparatively  short  distance  in  its  investigations  of  the 
starry  heavens,  and  a  great  many  mysterious  points  yet  remain 
to  be  explained.  The  phenomena  of  the  new  stars,  of  the  lost 
stars,  of  the  nebulous  stars,  of  the  variable  stars,  all  remain 
without  satisfactory  explanation.  Advances  are  constantly 
making;  and  reasoning  from  past  success,  the  future  may  be 
looked  forward  to  with  the  highest  anticipations.  The  confir- 
mation or  disproof  of  the  nebular  theory,  and  of  Miiedler's 
hypothesis  of  the  central  sun,  will  probably  in  a  few  years 
reward  the  diligent  and  unremitting  researches  of  philosophers. 

Leaving  the  region  of  the  fixed  stars,  there  now  remain  to  be 
considered  certain  other  celestial  bodies,  all  of  which,  from  their 
remarkable  appearance  and  changes,  and  some  of  them  from 
their  intimate  connection  with  the  comfort,  convenience,  and 
even  existence  of  man,  must  have  always  attracted  especial 
observation,  and  been  objects  of  the  most  intense  contemplation 
and  the  deepest  interest.  Most  of  these  bodies  are  situated 
within  the  limits  of  the  Zodiac.  The  most  important  of  them 
are,  the  Sun,  so  superior  to  all  the  heavenly  bodies  for  its 
apparent  magnitude,  for  the  light  and  heat  which  it  imparts,  for 
the  marked  effects  of  its  changes  of  position  in  regard  to  the 
Earth ;  and  the  Moon,  so  conspicuous  among  the  bodies  which 
give  light  by  night,  and  from  her  soft  and  silvery  brightness,  so 
pleasing  to  behold;  remarkable  not  only  for  changes  of  position, 
but  for  the  varied  phases  or  appearances  which  she  presents, 
as  she  waxes  from  her  crescent  form  through  all  her  different 
stages  of  increase  to  a  full  orb,  and  wanes  back  again  to  her 
former  distinguished  figure. 

The  partial  or  total  obscuration  of  these  two  bodies,  which 
sometimes  occurs, — darkness  taking  place  even  at  mid-day,  and 
the  face  of  night,  before  lighted  up  by  the  moon's  beams,  being 
suddenly  shaded  by  their  absence, — have  always  been  among 


THE   SOLAR   SYSTElvlT.  213 

the  most  striking  astronomical  phenomena;  and  so  powerful  in 
their  influence  upon  the  beholders,  as  to  fill  them  with  perplexity 
and  fear.  If  we  observe  these  two  bodies,  we  shall  find,  that, 
besides  their  apparent  diurnal  motion  across  the  heavens,  they 
exhibit  other  phenomena,  which  must  be  the  effect  of  motion. 
The  sun,  during  one  part  of  the  year,  will  be  seen  to  rise  every 
day  further  and  further  toward  the  north,  to  continue  longer  and 
longer  above  the  horizon,  to  be  more  and  more  elevated  at  mid- 
day, until  he  arrives  at  a  certain  limit;  and  then,  during  the 
other  part,  the  order  is  entirely  reversed.  The  moon  sometimes 
is  not  seen  at  all;  and  then,  when  she  first  becomes  visible, 
appears  in  the  west,  not  far  from  the  setting  sun,  with  a  slender 
crescent  form.  Every  night  she  appears  at  a  greater  distance 
from  the  setting  sun,  increasing  in  size,  until  at  length  she  is 
found  in  the  east,  just  as  the  sun  is  sinking  below  the  horizon 
in  the  west. 

The  sun,  if  his  motions  be  attentively  observed,  will  be  found 
to  have  another  motion,  opposite  to  his  apparent  diurnal  motion 
from  east  to  west.  This  may  be  perceived  distinctly,  if  we  no- 
tice, on  any  clear  evening,  any  bright  star,  which  is  first  visible 
after  sunset,  near  the  place  where  he  sunk  below  the  horizon. 
The  following  evening,  the  star  will  not  be  visible  on  account 
of  the  approach  of  the  sun,  and  all  the  stars  on  the  east  of  it 
will  be  successively  eclipsed  by  his  rays,  until  he  shall  have 
made  a  complete  apparent  revolution  in  the  heavens.  These  are 
the  most  obvious  phenomena  exhibited  by  these  two  bodies. 

There  are,  also,  situated  within  the  limits  of  the  zodiac,  cer- 
tain other  bodies,  which,  at  first  view,  and  on  a  superficial  exa- 
mination, are  scarcely  distinguishable  from  the  fixed  stars. 
But  observed  more  attentively,  they  will  be  seen  to  shine  with 
a  milder  and  steadier  light;  and  besides  being  carried  round 
with  the  stars,  in  the  apparent  revolution  of  the  great  celestial 
concave,  they  will  seem  to  change  their  places  in  the  concave 
itself.  Sometimes  they  are  stationary  ;  sometimes  they  appear 
to  be  moving  from  west  to  east,  and  sometimes  to  be  going  back 
again  from  east  to  west ;  being  seen  at  sunset  sometimes  in  the 
east,  and  sometimes  in  the  west,  and  always  apparently  chang- 
ing their  position  with  regard  to  the  earth,  each  other,  and  the 
other  heavenly  bodies.  From  their  wandering,  as  it  were,  in 
this  manner,  through  the  heavens,  they  were  called  by  the  Greeks 
r\tv»T3Li,  planets,  which  signifies  wanderers. 

There  also  sometimes  appear  in  the  heavens  bodies  of  a  very 
extraordinary  aspect,  which  continue  visible  for  a  considerable  pe- 
riod, and  then  disappear  from  our  view  ;  and  nothing  more  is  seen 
of  them,  it  may  be  for  years,  when  they  again  present  themselves, 
and  take  their  place  among  the  bodies  of  the  celestial  sphere. 
They  are  distinguished  from  the  planets  by  a  dull  and  cloudy 


214  GEOGRAPHY  OF  THE   HEAVENS. 

appearance,  and  by  a  train  of  light.  As  they  approach  the  sun, 
however,  their  faint  and  nebulous  light  becomes  more  and  more 
brilliant,  and  their  train  increases  in  length,  until  they  arrive  at 
their  nearest  point  of  approximation,  when  they  shine  with  their 
greatest  brilliancy.  As  they  recede  from  the  sun,  they  gradually 
lose  their  splendor,  resume  their  faint  and  nebulous  appearance, 
and  their  train  diminishes,  until  they  entirely  disappear.  They 
have  no  well  defined  figure ;  they  seem  to  move  in  every  possible 
direction,  and  are  found  in  every  part  of  the  heavens.  From 
their  train,  they  were  called  by  the  Greeks  K^*™/,  comets, 
which  signifies  having  long  hair. 

The  causes  of  these  various  phenomena  must  have  early  con- 
stituted a  very  natural  subject  of  inquiry.  Accordingly,  we 
shall  find,  if  we  examine  the  history  of  the  science,  that  in  very 
early  times  there  were  many  speculations  upon  this  subject,  and 
that  different  theories  were  adopted  to  account  for  these  celestial 
appearances. 

The  Egyptians,  Chaldeans,  Indians,  and  Chinese,  early  possessed 
many  astronomical  facts,  many  observations  of  important  phenomena, 
and  many  rules  and  methods  of  astronomical  calculation ;  and  it  has 
been  imagined,  that  they  had  the  ruins  of  a  great  system  of  astronomical 
science,  which,  in  the  earliest  ages  of  the  world,  had  been  carried  to  a 
great  degree  of  perfection,  and  that,  while  the  principles  and  explanations 
of  the  phenomena  were  lost,  the  isolated,  unconnected  facts,  rules  of  cal- 
culation, and  phenomena  themselves,  remained.  Thus,  the  Chinese, 
who,  it  is  generally  agreed,  possess  the  oldest  authentic  observations  on 
record,  have  recorded  in  their  annals  a  conjunction  of  five  planets  at  the 
same  time,  which  happened  2461  years  before  Christ,  or  100  years  be- 
fore the  flood.  By  mathematical  calculation,  it  is  ascertained  that  this 
conjunction  really  occurred  at  that  time.  The  first  observation  of  a  solar 
eclipse,  of  which  the  world  has  any  knowledge,  was  made  by  the  Chi- 
nese, 2128  years  before  Christ,  or  220  years  after  the  deluge.  It  seems, 
also,  that  the  Chinese  understood  the  method  of  calculating  eclipses ;  for, 
it  is  said  that  the  emperor  was  so  irritated  against  the  great  officers  of 
state  for  neglecting  to  predict  the  eclipse,  that  he  caused  them  to  be  put 
to  death.*  The  astronomical  epoch  of  the  Chinese,  according  to  Bailly, 
commenced  with  Fohi, -their  first  emperor,  who  flourished  2952  years 
before  the  Christian  era,  or  about  350  years  before  the  deluge. 

If  it  be  asked  how  the  knowledge  of  this  antediluvian  astronomy  was 
preserved  and  transmitted,  it  is  said  that  the  columns  on  which  it  was 
registered  have  survived  the  deluge,  and  that  those  of  Egypt^are  only 
copies,  which  have  become  originals,  now  that  the  others  have  been  for- 
gotten. The  Indians,  also,  profess  to  have  many  celestial  observations 
of  a  very  early  date.  The  Chaldeans  have  been  justly  celebrated  in  all 
ages  for  their  astronomical  observations.  When  Alexander  took  Baby- 

*  It  is  well  known  that  the  Chinese  have,  from  time  immemorial,  considered 
their  solar  eclipses  and  conjunctions  of  the  planets  ns  prognostics  of  importance 
to  the  empire,  and  that  they  have  been  predicted  us  a  matter  of  state  policy. 


THE   SOLAR  SYSTEM.  215 

ton.  his  preceptor,  Callistlienes,  found  a  series  of  Chaldean  observations, 
made  in  that  city,  and  extending  back,  with  little  interruption,  through  a 
period  of  1903  years  preceding  that  event.  This  would  carry  us  back 
to  at  least  2234  years  before  the  birth  of  Christ,  or  to  about  the  time  of 
the  dispersion  of  mankind  by  the  confusion  of  tongues.  Though  it  he 
conceded  that,  upon  this  whole  period  in  the  history  of  the  science,  the 
obscurity  of  very  remote  antiquity  must  necessarily  rest,  still  it  will  remain 
evident  that  the  phenomena  of  the  heavenly  bodies  had  been  observed 
with  great  attention,  and  had  been  a  subject  of  no  ordinary  interest. 

But,  however  numerous  or  important  were  the  observations  of  oriental 
antiquity,  they  were  never  reduced  to  the  shape  and  symmetry  of  a  regu- 
lar system. 

The  Greeks,  in  all  probability,  derived  many  notions  in  regard  to  this 
science,  and  many  facts  and  observations,  from  Egypt,  the  great  fountain 
of  ancient  learning  and  wisdom,  and  many  were  the  speculations  and 
hypotheses  of  their  philosophers.  In  the  fabulous  period  of  Grecian 
history,  Atlas,  Hercules,  Linus  and  Orpheus,  are  mentioned  as  persons 
distinguished  for  their  knowledge  of  astronomy,  and  for  the  improvements 
which  they  made  in  the  science.  But,  in  regard  to  this  period,  little 
is  known  with  certainty,  arid  it  must  be  considered,  as  it  is  termed, 
fabulous. 

The  first  of  the  Greek  philosophers  who  taught  astronomy, 
was  Thales,  of  Miletus.  He  flourished  about  640  years  before 
the  Christian  era.  Then  followed  Anaximander,  Anaximenes, 
Anaxagoras,  Pythagoras,  Plato.  Some  of  the  doctrines  main- 
tained by  these  philosophers  were — that  the  earth  was  round ; 
that  it  had  two  motions,  a  diurnal  motion  on  its  axis,  and  an  an- 
nual motion  around  the  sun ;  that  the  sun  was  a  globe  of  fire ; 
that  the  moon  received  her  light  from  the  sun ;  that  she  was 
habitable,  contained  mountains,  seas,  &c.;  that  her  eclipses  were 
caused  by  the  earth's  shadow ;  that  the  planets  were  not  de- 
signed merely  to  adorn  our  heavens;  that  they  were  worlds  of 
themselves;  and  that  the  fixed  stars  were  centers  of  distant 
systems.  Some  of  them,  however,  maintained  that  the  earth 
was  flat;  and  others,  that,  though  round,  it  was  at  rest  in  the 
center  of  the  universe. 

When  that  distinguished  school  of  philosophy  was  established 
at  Alexandria,  in  Egypt,  by  the  munificence  of  the  sovereigns  to 
whom  that  portion  of  Alexander's  empire  had  fallen,  astronomy 
received  a  new  impulse.  It  was  now,  in  the  second  century 
after  Christ,  that  the  first  complete  system  or  treatise  of  astro- 
nomy, of  which  we  have  any  knowledge,  was  formed.  All  be- 
fore had  been  unconnected  and  incomplete.  Ptolemy,  with  the 
opinions  of  all  antiquity,  and  of  all  the  philosophers  who  had 
preceded  him,  spread  out  before  him,  composed  a  work,  in  thir- 
teen books,  called  the  M^etxw  Ewr*%ts>  or  Great  System.  Re- 
jecting the  doctrine  of  Pythagoras,  who  taught  that  the  sun  was 
the  center  of  the  universe,  and  that  the  earth  had  a  diurnal  mo 


216  GEOGRAPHY  OF  THE  HEAVENS. 

tion  on  its  axis  and  an  annual  motion  around  the  sun,  as  contrary 
to  the  evidence  of  the  senses,  Ptolemy  endeavored  to  account  for 
the  celestial  phenomena,  by  supposing  the  earth  to  be  the  center 
of  the  universe,  and  all  the  heavenly  bodies  to  revolve  around  it. 
He  seems  to  have  entertained  an  idea,  in  regard  to  the  supposi- 
tion that  the  earth  revolved  on  its  axis,  similar  to  one  which 
some  entertain  even  at  the  present  day.  "  If,"  says  he,  "  there 
were  any  motion  of  the  earth,  common  to  it  and  all  other  heav- 
enly bodies,  it  would  certainly  precede  them  all,  by  the  excess 
of  its  mass  being  so  great;  and  animals,  and  a  certain  portion 
of  heavy  bodies,  would  be  left  behind,  riding  upon  the  air,  and 
the  earth  itself  would  very  soon  be  completely  carried  out  of  the 
heavens." 

In  explaining  the  celestial  phenomena,  however,  upon  his  hypothesis, 
he  met  with  a  difficulty  in  the  apparently  stationary  attitude  and  retro- 
grade motions  which  he  saw  the  planets  sometimes  have.  To  explain 
this,  however,  he  supposed  the  planets  to  revolve  in  small  circles,  which 
he  called  epicycles,  which  were,  at  the  same  time,  carried  around  the 
earth  in  larger  circles,  which  he  called  diiferents,  or  carrying  circles.  In 
following  out  his  theory,  and  applying  it  to  the  explanation  of  different 
phenomena,  it  became  necessary  to  add  new  epicycles,  and  to  have  re- 
course to  other  expedients,  until  the  system  became  unwieldy,  cumbrous, 
and  complicated.  This  theory,  although  astronomical  observations  con- 
tinued to  be  made,  and  some  distinguished  astronomers  appeared  from 
time  to  time,  was  the  prevailing  theory  until  the  middle  of  the  fifteenth 
century.  It  was  not,  however,  always  received  with  implicit  confidence ; 
nor  were  its  difficulties  always  entirely  unappreciated. 

Alphonso  X,  king  of  Castile,  who  flourished  in  the  thirteenth  century, 
when  contemplating  the  doctrine  of  the  epicycles,  exclaimed,  "  were  the 
universe  thus  constructed,  if  the  Deity  had  called  me  to  his  counsels  at 
the  creation  of  the  world,  I  could  have  given  him  good  advice."  He  did 
not,  however,  mean  any  impiety  or  irreverence,  except  what  was  directed 
against  the  system  of  Ptolemy. 

About  the  middle  of  the  fifteenth  century,  Copernicus,  a  native 
of  Thorn,  in  Prussia,  conceiving  a  passionate  attachment  to  the 
study  of  astronomy,  quitted  the  profession  of  medicine,  and  de- 
voted himself,  with  the  most  intense  ardor,  to  the  study  of  this 
science.  "  His  mind,"  it  is  said,  "  had  long  been  imbued  with 
the  idea  that  simplicity  and  harmony  should  characterize  the  ar- 
rangements of  the  planetary  system.  In  the  complication  and 
disorder  which,  he  saw,  reigned  in  the  hypothesis  of  Ptolemy, 
he  perceived  insuperable  objections  to  its  being  considered  as  a 
representation  of  nature." 

In  the  opinions  of  the  Egyptian  sages,  in  those  of  Pythagoras, 
Philolaus,  Aristarchus  and  Nicetas,  he  recognised  his  own  ear- 
liest conviction  that  the  earth  was  not  the  center  of  the  universe. 
His  attention  was  much  occupied  with  the  speculation  of  Mar- 


THE  SOLAR  SYSTEM.  217 

tinus  Capella,  who  placed  the  sun  between  Mars  and  the  moon, 
and  made  Mercury  and  Venus  revolve  around  him  as  a  center ; 
and  with  the  system  of  Appollonius  Pergceus,  who  made  all  the 
planets  revolve  around  the  sun,  while  the  sun  and  moon  were 
carried  around  the  earth,  in  the  center  of  the  universe. 

The  examination,  however,  of  these  hypotheses  gradually  ex- 
pelled the  difficulties  with  which  the  subject  was  beset,  and, 
after  the  labor  of  more  than  thirty  years,  he  was  permitted  to  see 
the  true  system  of  the  universe.  The  sun  he  considered  as  im- 
movable, in  the  center  of  the  system,  while  the  earth  revolved 
around  him,  between  the  orbits  of  Venus  and  Mars,  and  pro- 
duced, by  its  rotation  about  its  axis  all  the  diurnal  phenomena 
of  the  celestial  sphere.  The  other  planets  he  considered  as  re- 
volving about  the  sun,  in  orbits  exterior  to  that  of  the  earth. 

Thus  the  stations  and  retrogradations  of  the  planets  were  the 
necessary  consequence  of  their  own  motions,  combined  with  that 
of  the  earth  about  the  sun.  He  said  that,  "  by  long  observation, 
he  discovered,  that,  if  the  motions  of  the  planets  be  compared 
with  that  of  the  earth,  and  be  estimated  according  to  the  times 
in  which  they  perform  their  revolutions,  not  only  their  several 
appearances  would  follow  from  this  hypothesis,  but  that  it 
would  so  connect  the  order  of  the  planets,  their  orbits,  magni- 
tudes, and  distances,  and  even  the  apparent  motion  of  the  fixed 
stars,  that  it  would  be  impossible  to  remove  one  of  these  bodies 
out  of  its  place  without  disordering  the  rest,  and  even  the  whole 
of  the  universe  also." 

Soon  after  the  death  of  Copernicus,  arose  Tycho  Brahe,  born 
at  Knudstorp,  in  Norway,  in  1546.  Such  was  the  distinction 
which  he  had  attained  as  an  astronomer,  that,  when  dissatisfied 
with  his  residence  in  Denmark,  he  had  resolved  to  remove,  the 
king  of  Denmark,  learning  his  intentions,  detained  him  in  the 
kingdom,  by  presenting  him  with  the  canonry  of  Rothschild, 
with  an  income  of  2000  crowns  per  annum.  He  added  to  this 
sum  a  pension  of  1000  crowns,  gave  him  the  island  of  Huen, 
and  established  for  him  an  observatory,  at  an  expense  of  about 
200.000  crowns.  Here  Tycho  continued,  for  twenty-one  years, 
to  enrich  astronomy  with  his  observations.  His  "observations 
upon  the  moon  were  important,  and  upon  the  planets,  numerous 
and  precise,  and  have  formed  the  data  of  the  present  generaliza- 
tions in  astronomy.  He,  however,  rejected  the  system  of  Coper- 
nicus ;  considering  the  earth  as  immovable,  in  the  center  of  the 
system  ;  while  the  sun,  with  all  the  planets  and  comets  revolving 
around  him,  performed  his  revolution  around  the  earth;  and,  in 
the  course  of  twenty-four  hours,  the  stars  also  revolved  about  the 
central  body.  This  theory  was  not  as  simple  as  that  of  Coper- 
nicus, and  involved  the  absurdity  of  making  the  sun,  planets, 
&c.,  revolve  around  a  body  comparatively  insignificant. 
T 


218  GEOGRAPHY  OF  THE  HEAVENS. 

Near  the  close  of  the  15th  century,  arose  two  men,  who 
wrought  most  important  changes  in  the  science,  Kepler  and 
Galileo ;  the  former  a  German,  the  latter  an  Italian. 

Previous  to  Kepler,  all  investigations  proceeded  upon  the  sup- 
position that  the  planets  moved  in  circular  orbits,  which  had 
been  a  source  of  much  error.  This  supposition  Kepler  showed 
to  be  false.  He  discovered  that  their  orbits  were  ellipses.  The 
orbits  of  their  secondaries,  or  moons,  he  also  found  to  be  the  same 
curve.  He  next  determined  the  dimensions  of  the  orbits  of  the 
planets,  and  found  to  what  their  velocities  in  their  motions 
through  their  orbits,  and  the  times  of  their  revolutions,  were 
proportioned  ;  all  truths  of  the  greatest  importance  to  the  science. 

While  Kepler  was  making  these  discoveries  of  facts,  very 
essential  for  the  explanation  of  many  phenomena,  Galileo  was 
discovering  wonders  in  the  heavens  never  before  seen  by  the  eye 
of  man.  Having  improved  the  telescope,  and  applied  it  to  the 
heavens,  he  observed  mountains  and  valleys  upon  the  surface  of 
our  moon;  satellites  or  secondaries  were  discovered  revolving 
about  Jupiter ;  and  Venus,  as  Copernicus  had  predicted,  was 
seen  exhibiting  all  the  different  phases  of  the  moon,  waxing  and 
waning  as  she  does,  through  various  forms.  Many  minute  stars, 
not  visible  to  the  naked  eye,  were  descried  in  the  Milky  Way  ; 
and  the  largest  fixed  stars,  instead  of  being  magnified,  appeared 
to  be  small  brilliant  points,  an  incontrovertible  argument  in 
favor  of  their  immense  distance  from  us.  All  his  discoveries 
served  to  confirm  the  Copernican  theory,  and  to  show  the  ab- 
surdity of  the  hypothesis  of  Ptolemy. 

Although  the  general  arrangement  and  motions  of  the  planetary 
bodies,  together  with  the  figure  of  their  orbits,  had  been  thus 
determined,  the  force  or  power  which  carries  them  around  in 
their  orbits,  was  as  yet  unknown.  The  discovery  of  this  was 
reserved  for  the  illustrious  Newton.*  By  reflecting  on  the 
nature  of  gravity — that  power  which  causes  bodies  to  descend 
towards  the  center  of  the  earth — since  it  does  not  sensibly 
diminish  at  the  greatest  distance  from  the  center  of  the  earth  to 
which  we  can  attain,  being  as  powerful  on  the  loftiest  mountains 
as  it  is  in  the  deepest  caverns — he  was  led  to  imagine  that  it 
might  extend  to  the  moon,  and  that  it  might  be  the  power  which 
kept  her  in  her  orbit,  and  caused  her  to  revolve  around  the  earth. 
He  was  next  led  to  suppose  that  perhaps  the  same  power  carried 
the  primary  planets  around  the  sun.  By  a  series  of  calculations, 
he  was  enabled  at  length  to  establish  the  fact,  that  the  same 
force  which  determines  the  fall  of  an  apple  to  the  earth,  carries 
the  moons  in  their  orbits  around  the  sun. 

*  The  discovery  of  Newton  was  in  some  measure  anticipated  by  Copernicus, 
Kepler  and  Hooke. 


THE  SOLAR  SYSTEM.  219 

To  recapitulate  briefly  :  the  system  (not  hypothesis,  for  much 
of  it  has  been  established  by  mathematical  demonstration),  by 
which  we  are  now  enabled  to  explain  with  a  beautiful  simplicity 
the  different  phenomena  of  the  sun,  planets,  moons,  and  comets, 
is,  that  the  sun  is  the  central  body  in  the  system ;  that  the 
planets  and  comets  move  round  him  in  elliptical  orbits,  whose 
planes  are  more  or  less  inclined  to  each  other,  with  velocities 
bearing1  to  each  other*  a  certain  ascertained  relation,  and  in 
times  related  to  their  distances  ;  that  the  moons,  or  secondaries, 
revolve  in  like  manner,  about  their  primaries,  and  at  the  same 
time  accompany  them  in  their  motion  around  the  sun :  all 
meanwhile  revolving  on  axes  of  their  own ;  and  that  these  revo- 
lutions in  their  orbits,  are  produced  by  the  mysterious  power  of 
attraction.  The  particular  mode  in  which  this  system  is  ap- 
plied to  the  explanation  of  the  different  phenomena,  will  be  ex- 
hibited as  we  proceed  to  consider,  one  by  one,  the  several  bodies 
above  mentioned.  ( 

These  bodies,  thus  arranged  and  thus  revolving,  constitute 
what  is  termed  the  solar  system.  The  planets  have  been  divided 
into  two  classes,  primaries  and  secondaries.  The  latter  are  also 
termed  moons,  and  sometimes  satellites.  The  secondaries  are 
those  which  resolve  about  the  primaries.  There  have  been  dis- 
covered sixteen  primaries ;  namely,  Mercury,  Venus,  the  Earth, 
Mars,  Vesta,  Juno,  Ceres,  Pallas,  Astrea,  Hebe,  Iris,  Flora, 
Melis,  Jupiter,  Saturn,  Urauns,  Neptune.  Mercury  is  the  planet 
nearest  to  the  sun,  then  follow  the  others  in  the  order  in  which 
they  are  named.  The  nine  small  planets  between  Mars  and 
Jupiter  are  telescopic,  and  have  been  termed  asteroids.  There 
have  been  discovered  nineteen  secondaries,  or  moons.  Of  these, 
the  Earth  has  one,  Jupiter  four,  Saturn  seven,  Uranus  six,  and 
Neptune  one.  None  of  these,  except  our  moon,  are  visible 
without  telescopic  aid. 

We  proceed  to  examine  the  objects  constituting  the  solar 
system,  in  detail. 

*  The  orbits  or  paths  of  the  planets  wore  oiscovered  by  tracing  the  course 
of  the  planet  by  means  of  the  fixed  stars 


220        GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTER  VII. 

THE   SUN. 

THE  sun  is  a  vast  globe,  in  the  center  of  the  solar  system, 
dispensing  light  and  heat  to  all  the  planets,  and  governing  all 
their  motions. 

It  is  the  great  parent  of  vegetable  life,  giving  warmth  to  the 
seasons,  and  color  to  the  landscape.  Jts  rays  are  the  cause  of 
various  vicissitudes  on  the  surface  of  the  earth  and  in  the  at- 
mosphere. By  their  agency,  all  winds  are  produced,  and  the 
waters  of  the  sea  are  made  to  circulate  in  vapor  through  the  air, 
and  irrigate  the  land,  producing  springs  and  rivers. 

The  sun  is  by  far  the  largest  of  the  heavenly  bodies  whose 
dimensions  have  been  ascertained.  Its  diameter  is  something 
more  than  883,000  miles.  Consequently,  it  contains  a  volume 
of  matter  equal  to  fourteen  hundred  thousand  globes  of  the  size  of 
the  earth.  Of  a  body  so  vast  in  its  dimensions,  the  human 
mind,  with  all  its  efforts,  can  form  no  adequate  conception. 
The  whole  distance  between  the  earth  and  the  moon  would  not 
suffice  to  embrace  one-third  of  its  diameter. 

Were  the  sun  a  hollow  sphere,  perforated  with  a  thousand 
openings  to  admit  the  twinkling  of  the  luminous  atmosphere 
around  it — and  were  a  globe  as  large  as  the  earth  placed  at  its 
center,  with  a  satellite  as  large  as  our  moon,  and  at  the  same 
distance  from  it  as  she  is  from  the  earth,  there  would  be  present 
to  the  eye  of  a  spectator  on  the  interior  globe,  a  universe  as 
splendid  as  that  which  now  appears  to  the  uninstructed  eye — a 
universe  as  large  and  extensive  as  the  whole  creation  was  con- 
ceived to  be,  in  the  infancy  of  astronomy. 

The  next  thing  which  fills  the  mind  with  wonder,  is  the  dis- 
tance at  which  so  great  a  body  must  be  placed,  to  occupy,  ap- 
parently, so  small  a  place  in  the  firmament.  The  sun's  mean 
distance  from  the  earth  is  twelve  thousand  times  the  earth's 
diameter,  or  a  little  more  than  ninety-five  millions  of  miles. 
We  may  derive  some  faint  conception  of  such  a  distance,  by 
considering  that  the  swiftest  steamboats,  which  ply  our  waters 
at  the  rate  of  two  hundred  miles  a  day,  would  not  traverse  it  in 
thirteen  hundred  years  ,•  and,  that  a  cannon  ball,  flying  night  and 
day,  at  the  rate  of  sixteen  miles  a  minute,  would  not  reach  it  in 
eleven  years. 


THE  SUN.  221 

The  sun,  when  viewed  through  a  telescope,  presents  the  ap- 
pearance of  an  enormous  globe  of  fire,  frequently  in  a  state  of 
violent  agitation  or  ebullition ;  dark  spots  of  irregular  form, 
rarely  visible  to  the  naked  eye,  sometimes  pass  over  his  disk, 
from  east  to  west,  in  the  period  of  nearly  fourteen  days. 

These  spots  are  usually  surrounded  by  a  penumbra,  and  that, 
by  a  margin  of  light,  more  brilliant  than  that  of  the  sun.  A  spot 
when  first  seen  on  the  eastern  edge  of  the  sun,  appears  like  a 
line  which  progressively  extends  in  breadth,  till  it  reaches  the 
middle,  when  it  begins  to  contract,  and  ultimately  disappears, 
at  the  western  edge.  In  some  rare  instances,  the  same  spots 
re-appear  on  the  east  side,  and  are  permanent  for  two  or  three 
revolutions.  But,  as  a  general  thing,  the  spots  on  the  sun  are 
neither  permanent  nor  uniform.  Sometimes  several  small  ones 
unite  into  a  large  one ;.  and,  again,  a  large  one  separates  into 
numerous  small  ones.  Some  continue  several  days,  weeks,  and 
even  months,  together;  while  others  appear  and  disappear, 
in  the  course  of  a  few  hours.  Those  spots  that  are  formed 
gradually,  are,  for  the  most  part,  as  gradually  dissolved  ;  whilst 
those  that  are  suddenly  formed,  generally  vanish  as  quickly. 

It  is  the  general  opinion,  that  spots^m  the  sun  were  first  dis- 
covered by  Galileo,  in  the  beginning  OT  the  year  1611  ;  though 
Scheiner,  Harriot,  and  Fabricius,  observed  them  about  the  same 
time.  During  a  period  of  eighteen  years  from  this  time,  the  sun 
was  never  found  entirely  clear  of  spots,  excepting  a  few  days  in 
December,  1624 ;  at  other  times,  they  were  frequently  seen, 
twenty  or  thirty  at  a  time,  and  in  1625,  upwards  of  fifty  were 
seen  at  once.  From  1650  to  1670,  scarcely  any  spots  were  to 
be  seen;  and,  from  1676  to  1684,  the  orb  of  the  sun  presented 
an  unspotted  disk.  Since  the  beginning  of  the  eighteenth  century 
scarcely  a  year  has  passed,  in  which  spots  have  not  been  visi- 
ble, and  frequently  in  great  numbers.  In  1799,  Dr.  Herschel 
observed  one  nearly  30,000  miles  in  breadth. 

A  single  second  of  angular  measure,  on  the  sun's  disk,  as  seen  from 
the  earth,  corresponds  to  462  miles';  and  a  circle  of  this  diameter  (con- 
taining therefore  nearly  220,000  square  miles)  is  the  least  space  which 
can  be  distinctly  discerned  on  the  sun  as  a  visible  area,  even  by  the  most 
powerful  glasses.  Spots  have  been  observed,  however,  whose  linear 
diameter  has  been  more  than  44,000  miles ;  and,  if  some  records  are  to 
be  trusted,  of  even  still  greater  extent. 

Dr.  Dick,  in  a  letter  to  the  author,  says,  "  I  have  for  many  years  ex- 
amined the  solar  spots  with  considerable^  minuteness,  and  have  several 
times  seen  spots  which  were  not  less  than  the  one-twenty-fiflh  part  of  the 
sun's  diameter,  which  would  make  them  about  22,192  miles  hi  diameter, 
yet  they  were  visible  neither  to  the  naked  eye,  nor  through  an  opera 
glass,  magnifying  about  three  times.  And,  therefore,  if  any  spots  have 
been  visible  to  the  naked  eye — which  we  must  believe,  unless  we  refuse 
T2 


222  GEOGRAPHY  OF   THE  HEAVENS. 

respectable  testimony — they  could  not  have  been  much  less  than  50,000 
miles  in  diameter." 

The  apparent  motion  of  these  spots  over  the  sun's  surface,  is 
continually  varying  in  its  direction.  Sometimes  they  seem  to 
move  across  it  in  straight  lines,  at  others  in  curve  lines.  These 
phenomena  may  be  familiarly  illustrated  in  the  following 
manner. 

Fig.  1.  Fig.  2. 


m  w>#  19     *i 

»oTUii  ••»«•»         j 
<fl*'-»IW«       ^ 

Let  E  E  represent  the  ecliptic;  N  S.  its  north  and  south  poles,  M  the  point 
where  the  spot  enters,  and  m  the  point  where  it  leaves  the  sun's  disk.  At  the 
end  of  November,  and  the  beginning  of  December,  the  spot  will  appear  to 
move  downwards,  across  the  sun's  disk,  from  left  to  right,  describing  the 
straight  lines  Mm,  Fig  1  ;  soon  after  this  period,  these  lines  begin  gradually 
to  be  inflected  towards  the  north,  till  about  the  end  of  February,  or  the  begin- 
ning'of  March,  when  they  de^ribe  rfhe  curve  lines  represented  in  Fig.  2  After 
the  beginning  of  March,  the  curvature  decreases,  till  the  latter  end  of  May.  or 
the  beginning  of  June,  when  they  again  describe  straight  lines  tending  up- 
wards, as  in  Fig.  3.  By  and  by  these  straight  lines  begin  to  be  inflected  down- 
wards, till  about  the  beginning  of  September,  when  they  take  the  form  of  a 
curve,  having  its  convex  side  towards  the  south  pole  of  the  sun,  as  in  Fig.  4. 

Fig.  3.  Fig.  4. 


.; 

As  these  phenomena  are  repeated  every  year,  in  the  same 
order,  and  belong  to  all  the  spots  that  have  been  perceived  upon 
the  sun's  disk,  it  is  concluded,  with  good  reason,  that  these 
spots  adhere  to  the  surface  of  the  sun,  and  revolve  with  it,  upon 
an  axis,  inclined  a  little  to  the  plane  of  the  ecliptic.  The  ap- 
parent revolution  of  a  spot,  from  any  particular  point  of  the 
sun's  disk,  to  the  same  point  again,  is  accomplished  in  27  days, 
7  hours,  26  minutes,  and  24  seconds;  but  during  that  time,  the 
spot  has,  in  fact,  gone  through  one  revolution,  together  with  an 
arc,  equal  to  that  described  by  the  sun,  in  his  orbit,  in  the  same 
time,  which  reduces  the  time  of  the  sun's  actual  rotation  on  his 
axis,  to  25  days,  9  hours,  and  36  minutes. 


THE  SUN.  223 

The  part  of  the  sun's  disk  not  occupied  by  spots,  is  far  from 
being  uniformly  bright.  Its  ground  is  finely  mottled  with  an 
appearance  of  minute,  dark  dots,  or  pores.  Herschel  remarks 
that  these  pores,  when  attentively  watched,  are  found  to  be  in  a 
constant  state  of  change.  This  is  certainly  an  error,  if  the  change 
spoken  of  is  one  visible  under  the  eye;  for  I  have  watched  these 
minute  pores  with  the  greatest  scrutiny,  but  never  found  while 
under  the  eye,  the  slightest  change. 

The  elder  Herschel  conceived  that  the  sun's  body  was  dark 
or  opake,  and  that  it  was  surrounded  by  a  luminous  ocean  or 
atmosphere  of  vast  extent.  Beneath  this  and  above  the  sun's 
surface  he  thought  there  might  "exist  a  stratum  of  clouds,  and 
with  this  constitution  he  proceeds  to  account  for  the  phenomena 
of  the  spots.  The  black  core  of  the  spot  he  regards  as  the  solid 
opake  body  of  the  sun,  seen  through  an  opening  in  the  lumin- 
ous atmosphere  and  in  the  floating  clouds  below  it,  while  the 
partial  shade  or  penumbra  he  attributes  to  the  light  reflected 
from  the  cloudy  stratum. 

I  have  watched  the  solar  spots  for  three  years  with  great  at- 
tention, and  find  it  quite  impossible  to  reconcile  the  phenomena 
with  any  theory  which  supposes  extreme  mobility  in  the  particles 
composing  the  exterior  surface.  The  outline  of  the  penumbra 
is  seen  sharp,  keenly  defined  and  cutting  directly  across  the 
small  mottlings  or  pores,  as  though  the  exterior  were  a  crust, 
hard  and  solid,  melted  out  from  under  by  some  internal  agent. 
Again,  the  outline  of  the  dark  core  of  the  spot  eats  into  the  penum- 
bra sharp  and  sudden,  sometimes  in  long  black  filaments  of  ir- 
regular shape,  but  always  without  any  such  gradual  shading  off 
as  might  be  anticipated  in  case  great  mobility  existed  among  the 
particles  of  matter  composing  the  exterior  coating  of  the  sun. 

The  German  astronomer  Schwabe,  of  Dessau,  has  discovered 
the  remarkable  fact,  that  there  is  a  periodical  return  of  the  solar 
spots.  In  1828  a  very  large  number  of  spots  were  observed. 
Then  for  five  years  the  number  decreased  regularly,  until  in  1833 
the  spots  counted  reached  a  minimum;  an  increase  now  com- 
menced, and  continued  yearly  up  to  1838,  when  a  maximum 
number  was  reached.  Then  a  decline  commenced,  and  continued 
to  1843,  when  but  few  spots  were  seen.  Since  that  year  the 
number  visible  has  been  gradually  on  the  increase  ;  and  during 
this  year,  1848,  I  have  never  seen  the  sun  without  spots,  and 
many  groups  have  been  very  large. 

In  examining  the  sun,  I  have  occasionally  seen  that  curious  phe- 
nomenon, called  by  the  Germans"  Lichtflacken  "  luminousflaJt.es. 
They  are  brilliant  points  of  swiftly  moving  light  seen  near  the 
sun,  and  apparently  as  bright  or  even  brighter  than  the  sun  itself. 
Some  suppose  them  to  be  motes  floating  in  the  upper  regions  of 


224  GEOGRAPHY  OF  THE  HEAVENS. 

the  air;  while  others  resist  this  hypothesis,  without  propounding 
any  more  satisfactory  one. 

We  append  the  following  table,  exhibiting  the  elements  of  the 
sun  as  determined  for  the  1st  of  January,  1801. 

Mean  longitude,  280°  39'  10".  2 

Longitude  of  perigee,  -         279    30  05  .0 

Greatest  equation  of  center,     -  -  I    55  27  .3 

Soeular  diminution  of  center,  -  -  17  .2 

Inclination  of  axis  (82£°),    -  -  7    30  00  .0 

Motion  in  a  mean  solar  day,  -  -  59  08  .3 

Motion  of  perigee  in  365  days,  -  -         101.9 

Apparent  semidiameter,  -  -  16  00  .0 

Mean  horizontal  parallax,       -  -  -  8  .6 

Rotation  on  its  axis  in  sidereal  days,  -  25  d.  .01154 

Time  of  passing  one  degree  of  mean  longitude,    24  h.  20  m.  58  s.  .14 
Eccentricity  of  orbit  (radius  unity),  -  -          .0168531 

Volume  earth  as  unity,       ...  1 .384,472 

Mass  earth  as  unity,  -  -  -  354,936 

Mean  distance  (95,000,000  miles),  earth's  rad.  unity,  23,984 

Density,  or  ratio  of  mass  to  volume,  -  -  0.2543 

True  diameter  (883,000  miles),  in  diameters  of  earth,        -      1 1 1.454 

Accompanying  the  sun,  there  is  an  extraordinary  luminous 
appearance,  called  the  zodiacal  light,  which  is  seen  at  certain 
seasons  of  the  year  after  sunset,  or  before  sunrise,  like  the  faint 
tail  of  a  comet,  extending  upward  from  the  sun,  in  the  plane  of 
the  ecliptic.  Dr.  Herschel  conceived  this  phenomenon  to  be  a 
nebulous  atmosphere,  yet  uncondensed,  and  surrounding  the  sun, 
whose  lenticular  shape  arose  from  its  rotary  motion.  There  is 
great  difficulty  in  explaining  this  phenomenon,  on  the  theory  of 
gravitation  alone,  for  gravity  will  not  permit  material  particles 
to  remain  at  so  great  a  distance  from  the  sun  as  the  extreme 
particles  constituting  the  zodiacal  light. 

May  not  the  same  power  which  operates  (as  we  shall  here- 
after see)  to  produce  the  tails  of  comets,  on  their  near  approach 
to  the  sun,  be  active  in  supporting,  by  repulsion,  the  particles 
of  the  zodiacal  light  in  their  great  elevation  above  the  sun's 
surface?  We  shall  again  refer  to  this. subject,  when  we  come 
to  treat  of  the  comets. 

The  direct  light  of  the  sun  is  greatly  diminished  by  the  atmo- 
sphere by  which  it  is  surrounded.  This  is  manifest  from  the 
fact  that  the  edsre  or  disk  is  far  less  luminous  than  the  central 
portion,  which  is  directly  the  reverse  of  what  ought  to  be  exhib- 
ited in  case  no  cause  operates  to  absorb  the  light. 

The  lirrht  of  the  sun  has  been  estimated  to  be  more  than 
800,000  times  greater  than  that  of  the  moon.  The  most  intense 
artificial  light  yet  discovered,  when  seen  against  the  sun,  looks 
like  a  black  spot  on  its  surface. 


MERCURY. 


MERCURY. 

MERCURY  is  the  nearest  planet  to  the  sun  that  has  yet  been  dis- 
covered ;  and,  with  the  exception  of  the  asteroids,  is  the  small- 
est. Its  diameter  is  only  3140  miles.  Its  bulk,  therefore,  is 
about  17  times  less  than  that  of  the  earth.  It  would  require 
more  than  twenty  millions  of  such  globes  to  compose  a  body 
equal  to  the  sun. 

It  revolves  on  its  axis,  from  west  to  east,  in  24  hours,  5  mi- 
nutes, and  28  seconds;  which  makes  its  day  about  10  minutes 
longer  than  ours.  It  performs  its  revolution  about  the  sun  in  a 
fpw  minutes  less  than  88  days,  and  at  a  mean  distance  of  nearly 
thirty-seven  millions  of  miles.  The  length  of  Mercury's  year, 
therefore,  is  equal  to  about  three  of  our  months. 

The  rotation  of  a  planet  on  it  axis  constitutes  its  day ;  its  revolution 
about  the  sun  constitutes  its  year. 

Mercury  is  not  only  the  most  dense  of  all  the  planets,  but  re- 
ceives from  the  sun  seven  times  as  much  light  and  heat  as  the 
earth.  The  truth  of  this  estimate,  of  course,  depends  upon  the 
supposition  that  the  intensity  of  solar  light  and  heat,  at  the 
planets,  varies  inversely  as  the  squares  of  their  distances  from 
the  sun. 

This  law  of  analogy,  did  it  exist  with  rigorous  identity  at  all 
the  planets,  would  be  no  argument  against  their  being  inhabited  ; 
because  we  are  bound  to  presume  that  the  Allwise  Creator  has 
attempered  every  dwelling-place  in  his  empire  to  the  physical 
constitution  of  the  beings  which  he  has  placed  in  it. 

From  a  variety  of  facts  which  have  been  observed  in  relation  to  the 
production  of  caloric,  it  does  not  appear  probable  that  the  degree  of  heat 
on  the  surface  of  the  different  planets  depends  on  their  respective  dis- 
tances from  the  sun.  It  is  more  probable  that  it  depends  chiefly  on  the 
distribution  of  the  substance  of  caloric  on  the  surfaces,  and  throughout 
the  atmospheres  of  these  bodies,  in  different  quantities,  according  to  the 
different  situations  which  they  occupy  in  the  solar  system ;  and  that  these 
different  quantities  of  caloric  are  put  into  action  by  the  influence  of  the 
solar  rays,  so  as  to  produce  that  degree  of  sensible  heat  requisite  to  the 
wants,  and  to  the  greatest  benefit  of  each  of  the  planets.  On  this  hypo- 
thesis, which  is  corroborated  by  a  great  variety  of  facts  and  experiments, 
there  may  be  no  more  sensible  heat  expenenced  on  the  planet  Mercury 
than  on  the  surface  of  Herschel,  which  is  fifty  times  further  removed  from 
the  sun. 

Owing  to  the  dazzling  brightness  of  Mercury,  the  swiftness 
of  its  motion,  and  its  nearness  to  the  sun,  astronomers  have 
made  but  comparatively  few  discoveries  respecting  it.  When 
viewed  through  a  telescope  of  considerable  magnifying  power, 


226  GEOGRAPHY   OF   THE   HEAVENS. 

it  exhibits,  at  different  periods,  all  the  various  phases  of  the 
moon ;  except  that  it  never  appears  quite  full,  because  its  en- 
lightened hemisphere  is  never  turned  directly  toward  the  earth, 
only  when  it  is  behind  the  sun,  or  so  near  to  it  as  to  be  hidden  by 
the  splendor  of  its  beams.  Its  enlightened  hemisphere  being 
thus  always  turned  toward  the  sun,  and  the  opposite  one  being 
always  dark,  prove  that  it  is  an  opake  body,  similar  to  the 
earth,  shining  only  in  the  light  which  it  receives  from  the  sun. 
The  rotation  of  Mercury  on  its  axis  was  determined,  from  the 
daily  position  of  its  horns,  by  M.  Schroeter,  who  not  only  dis- 
covered spots  upon  its  surface,  but  several  mountains  in  its 
southern  hemisphere,  one  of  which  was  10^  miles  high — nearly 
three  times  as  high  as  Chimborazo,  in  South  America. 

It  is  worthy  of  observation,  that  the  highest  mountains  which  have 
been  discovered  in  Mercury,  Venus,  the  moon,  and,  perhaps,  we  may 
add,  the  earth,  are  all  situated  hi  their  southern  hemispheres. 

During  a  few  days  in  March  and  April,  August  and  Septem- 
ber, Mercury  may  be  seen  for  several  minutes,  in  the  morning  or 
evening  twilight,  when  its  greatest  elongations  happen  in  those 
months ;  in  all  other  parts  of  its  orbit,  it  is  too  near  the  sun  to 
be  seen  by  the  naked  eye.  The  greatest  distance  that  it  ever 
departs  from  the  sun,  on  either  side,  varies  from  16°  12'  to  28° 
48',  alternately. 

The  revolution  of  Mercury  about  the  sun,  like  that  of  all  the 
planets,  is  performed  from  west  to  east,  in  an  orbit  which  is 
nearly  circular.  Its  apparent  motion,  as  seen  from  the  earth,  is, 
alternately,  from  west,  to  east,  and  from  east  to  west,  nearly  in 
straight  lines;  sometimes,  directly  across  the  face  of  the  sun, 
but  at  all  other  times  either  a  little  above  or  a  little  below  it. 

Being  commonly  immersed  in  the  sun's  rays  in  the  evening, 
and  thus  continuing  invisible  until  it  emerges  from  them  in  the 
morning,  it  appeared  to  the  ancients  like  two  distinct  stars.  A 
long  series  of  observations  was  requisite  before  they  recognized 
the  identity  of  the  star  which  was  seen  to  recede  from  the  sun 
in  the  morning  with  that  which  approached  it  in  the  evening. 
But  as  the  one  was  never  seen  until  the  other  disappeared,  both 
were  at  last  found  to  be  the  same  planet,  which  thus  oscillated 
on  each  side  of  the  sun. 

Mercury's  oscillation  from  west  to  east,  or  from  east  to  west, 
is  really  accomplished  in  just  half  the  time  of  its  revolution, 
which  is  about  44  days;  but  as  the  earth,  in  the  meantime,  fol- 
lows the  sun  in  the  same  direction,  the  apparent  elongations  will 
be  prolonged  to  between  55  and  65  days. 

The  passage  of  Mercury  over  the  sun's  disk  is  denominated  a 
transit.  This  would  happen  in  every  revolution,  if  the  orbit  lay 
in  the  same  plane  with  the  orbit  of  the  earth.  But  it  does  not; 


MERCURY. 


227 


1707  May  5. 
1710  Nov.  6. 
1723  Nov.  9. 
1736  Nov.  10. 
1740  Nov.  2. 
1743  Nov.  4. 
1753  May  5. 
1756  Nov.  6 
1769  Nov.  9. 

1776  Nov.  2. 
1782  Nov.  12. 
1786  May  3. 
1789  Nov.  5. 
1799  May  7. 
1802  Nov.  8. 
181  5  Nov.  11. 
1822  Nov.  4. 
1832  May  5. 

1835  Nov.  7. 
J  845  May  8. 
1848  Nov.  9. 
1861  Nov.  11. 
1868  Nov.  4. 
1878  May  6. 
1881  Nov.  7. 
1891  May  9. 
1894  Nov.  10. 

it  cuts  the  earth's  orbit  in  two  opposite  points,  as  the  ecliptic 
does  the  equator,  but  at  an  angle  three  times  less. 

These  points  of  intersection  are  called  the  nodes  of  the  orbit. 
Mercury's  ascending  node  is  in  the  16th  degree  of  Taurus;  its 
descending  node  in  the  16th  degree  of  Scorpio.  As  the  earth 
passes  these  nodes  in  November  and  May,  the  transits  of 
Mercury  must  happen,  for  many  ages  to  come,  in  one  of  these 
months. 

The  following  is  a  list  of  all  the  transits  of  Mercury,  from  the  time  the 
first  was  observed,  by  Gassendi,  November  "6,  1631,  to  the  end  of  the 
present  century. 

1631  Nov.  6. 

1644  Nov.  6. 

1651  Nov.  2. 

1661  May  3. 

1664  Nov.  4. 

1674  May  6. 

1677  Nov.  7. 

1690  Nov.  9. 

1697  Nov.  2. 

By  comparing  the  mean  motion  of  any  of  the  planets  with  the  mean 
motion  of  the  earth,  we  may,  in  like  manner,  determine  the  periods  in 
which  these  bodies  will  return  to  the  same  points  of  their  orbit,  and  the 
same  positions  with  respect  to  the  sun.  The  knowledge  of  these  periods 
will  enable  us  to  determine  the  hour  when  the  planets  rise,  set,  and  pass 
the  meridian,  and,  in  general,  all  the  phenomena  dependent  upon  the  re- 
lative position  of  the  earth,  the  planet,  and  the  sun ;  for  at  the  end  of 
one  of  these  periods  they  commence  again,  and  all  recur  in  the  same  or- 
der. We  have  only  to  find  a  number  of  sidereal  years,  in  which  the 
planet  completes  exactly,  or  very  nearly,  a  certain  number  of  revolutions ; 
that  is,  to  find  such  a  number  of  planetary  revolutions  as,  when  taken 
together,  shall  be  exactly  equal  to  one,  or  any  number  of  revolutions  of 
the  earth.  In  the  case  of  Mercury,  this  ratio  will  be  as  87.969  is  to 
365.256.  Whence  We  find,  that— 

7  periodical  revolutions  of  the  earth  are  equal  to  29  of  Mercury  : 

1 3  periodical  revolutions  of  the  earth  are  equal  to  54  of  Mercury : 

33  periodical  revolutions  of  the  earth  are  equal  to  137  of  Mercury  : 

46  periodical  revolutions  of  the  earth  are  equal  to  191  of  Mercury. 
Therefore,  transits  of  Mercury,  at  the  same  node,  may  happen  at  intervals 
of  7,  13,  33,  46,  &c.,  years.  Transits  of  Venus,  as  well  as  eclipses  of 
the  sun  and  moon,  are  calculated  upon  the  same  principle. 

The  sidereal  revolution  of  a  planet  respects  its  absolute  motion,  and  is 
measured  by  the  time  the  planet  takes  to  revolve  from  any  fixed  star  to 
the  same  star  again. 

The  synodical  revolution  of  a  planet  respects  its  relative  morion,  and 
is  measured  by  the  time  that  a  planet  occupies  in  coming  back  to  the 
same  position,  with  respect  to  the  earth  and  the  sun. 

The  sidereal  revolution  of  Mercury  is  87  d.  23  h.  15m.  44s.     Its 


228  GEOGRAPHY  OF  THE  HEAVENS. 

si/nodical  revolution  is  found  by  dividing  the  whole  circumference  of 
360°  by  its  relative  motion  in  respect  to  the  earth.  Thus,  the  mean 
daily  motion  of  Mercury  is  14'  32".555 ;  that  of  the  earth  is  3548".  3 18; 
and  their  diiference  is  11184".237,  being  Mercury's  relative  motion,  or 
what  it  gains  on  the  earth  every  day.  Now,  by  simple  proportion, 
1 1 184".237  is  to  1  day  as  360°  is  to  115  d.  21  h.  3  m.  25  s.,  the  period 
of  a  synodical  revolution  of  Mercury. 

The  absolute  motion  of  Mercury  in  its  orbit,  is  109,757  mile? 
an  hour;  that  of  the  earth,  is  68,288  miles:  the  difference, 
41,469  miles,  is  the  m'ean  relative  motion  of  Mercury,  with 
respect  to  the  earth.  The  transit  of  Mercury  across  the  disk  of 
the  sun,  which  occurred  on  the  8th  of  May,  1845,  was  observed 
at  the  Cincinnati  observatory.  By  the  new  tables  of  Leverrier, 
its  place  was  predicted,  so  that  the  various  contacts  with  the 
sun  took  place  to  within  sixteen  seconds  of  the  computed  time. 
The  planet  was  seen  very  distinctly  as  a  round  black  spot  on 
the  bright  surface  of  the  sun.  The  density  of  the  planet,  and 
its  absolute  diameter,  enable  us  to  determine  the  force  of  gravi- 
tation at  its  surfaces.  A  heavy  body  would  fall  through  17.7 
feet  per  second  on  Mercury,  and  a  pound  of  matter  removed 
from  the  earth  to  the  planet  would  weigh  1,106  pounds. 

These  are  the  elements  of  Mercury  for  mean  noon,  Green- 
wich, 1st  Jan.  1801. 

Mean  sidereal  revolution,     -  -  87  d.  23  h.  15  m.  43  s.  .9 

Mean  longitude,  -  -  -  166°  00'  48".6 

Longitude  of  perihelion,  -  -  -  74  21    46  .9 

Annual  motion  of  the  line  of  apsides,      -  -  -  5  .8 

Ditto,  referred  to  the  ecliptic,  -  •  -  55  .9 

Longitude  of  the  ascending  node,  ...  45°  37' 30  .9 

Motion  of  ditto,  west  per  annum,      -  7  .8 

Ditto,  east  referred  to  the  ecliptic,  -  -  -  42  .3 

Mean  orbital  motion  in  a  solar  day,  -  -  4°  05'  32  .6 

Inclination  of  orbit,  -  -  -•         -70010.0 

Eccentricity  of  orbit,  half  major,  axis  unity  -         0,210,551,494 

Decrease  of  ditto,  in  a  century,  -  -  0,000,003,866 

Greatest  equation  of  center,  -  -  -         23°  39' 51  ".0 

Increase  of  ditto,  in  a  century,  ...  1  .6 

Axical  rotation,  -  -  24  h.  05  m.  28  s.  .3 

Mean  apparent  diameter,  -  -        «te*7  .        •  6".9 

True  diameter  (3140  miles)  earth  as  unity,          >ff>  tS5  0  .398 

Minimum  elongation,  ...  16°  12' 00" 

Maximum  ditto,  -  •  •  •  28    48  00 

Volume  earth  as  unity,  -        ,  '  • '. ,       -„•-  -  0,063 

Mass  sun  as  unity,  -  0,000,000,4936 

Mean  distance  (36,  000,000  miles)  earths  as  unity,  0,3870981 

' 


VENUS.  229 


VENUS. 

THKRE  are  but  few  persons  who  have  not  observed  a  beauti- 
ful star  in  the  west,  a  little  after  sunset,  called  the  evening  *tar. 
This  star  is  Venus.  It  is  the  second  planet  from  the  sun.  It  is 
the  brightest  star  in  the  firmament,  and  on  this  account  easily 
distinguished  from  the  other  planets. 

If  we  observe  this  planet  for  several  days,  we  shall  find  that 
it  does  not  remain  constantly  at  the  same  distance  from  the  sun, 
but  that  it  appears  to  approach,  or  recede  from  him,  at  the  rate 
of  about  three-fifths  of  a  degree  every  day ;  and  that  it  is  some- 
times on  the  east  side  of  him,  and  sometimes  on  the  west,  thus 
continually  oscillating  backward  and  forward  between  certain 
limits. 

As  Venus  never  departs  quite  48°  from  the  sun,  it  is  never 
seen  at  midnight,  nor  in  opposition  to  that  luminary;  being  visi- 
ble only  about  three  hours  after  sunset,  and  as  long  before  sun- 
rise, according  as  its  right  ascension  is  greater  or  less  than  that 
of  the  sun.  At  first  we  behold  it  only  a  few  minutes  after 
sunset;  the  next  evening  we  hardly  discover  any  sensible 
change  in  its  position ;  but  after  a  few  days,  we  perceive  that  it 
has  fallen  considerably  behind  the  sun,  and  that  it  continues  to 
depart  farther  and  farther  from  him,  setting  later  and  later  every 
evening,  until  the  distance  between  it  and  the  sun,  is  equal  to 
a  little  more  than  half  the  space  from  the  horizon  to  the  zenith, 
or  about  46°. 

It  now  begins  to  return  toward  the  sun,  making  the  same 
daily  progress  that  it  did  in  separating  from  him,  and  to  set 
earlier  and  earlier  every  succeeding  evening,  until  it  finally  sets 
with  the  sun,  and  is  lost  in  the  splendor  of  his  light. 

A  few  days  after  the  phenomena  we  have  now  described,  we 
perceive,  in  the  morning,  near  the  eastern  horizon,  a  bright 
star  which  was  not  visible  before.  This  also  is  Venus,  which 
is  now  called  the  morning  star.  It  departs  farther  and  farther 
from  the  sun,  rising  a  little  earlier  every  day,  until  it  is  seen 
about  46°  west  of  him,  where  it  appears  stationary  for  a  few 
days;  then  it  resumes  its  course  towards  the  sun,  appearing 
later  and  later  every  morning,  until  it  rises  with  the  sun,  and 
we  cease  to  behold  it.  In  a  few  days,  the  evening  star  again 
appears  in  the  west,  very  near  the  setting  sun,  and  the  same 
phenomena  are  again  exhibited.  *  Such  are  the  visible  appear- 
ances of  Venus. 

Venus  revolves  about  the  sun  from  west  to  east  in  924|  days, 
at  the  distance  of  about  68,000,000    of  miles,  moving   in  her 
V 


230  GEOGRAPHY  OF   THE   HEAVENS. 

orbit  at  the  rate  of  eighty  thousand  miles  an  hour.  She  turns 
around  on  her  axis  once  in  23  hours,  21  minutes,  and  7  seconds. 
Thus  her  day  is  about  25  minutes  shorter  than  ours,  while  her 
year  is  equal  to  7^  of  our  months,  or  32  weeks. 

The  mean  distance  of  the  earth  from  the  sun,  is  estimated  at 
95,000,000  of  miles,  and  that  of  Venus  being  68,000,000,  the 
diameter  of  the  sun,  as  seen  from  Venus,  will  be  to  his  diame- 
ter as  seen  from  the  earth,  as  95  to  68,  and  the  surface  of  his 
disk  as  the  square  of  95  to  the  square  of  68,  that  is,  as  9025  to 
4626,  or  as  2  to  1  nearly.  The  intensity  of  light  and  heat  being 
inversely  as  the  squares  of  their  distances  from  the  sun,  Venus 
receives  twice  as  much  light  and  heat  as  the  earth. 

Her  orbit  is  within  the  orbit  of  the  earth  ;  for  if  it  were  not, 
she  would  be  seen  as  often  in  opposition  to  the  sun,  as  in  con- 
junction with,  him;  but  she  was  never  seen  rising  in  the  east, 
while  the  sun  was  setting  in  the  west.  Nor  was  she  ever 
seen  in  quadrature,  or  on  the  meridian,  when  the  sun  was 
either  rising  or  setting.  Mercury  being  about  23°  from  the 
sun,  and  Venus  46°,  the  orbit  of  Venus  must  be  outside  of  the 
orbit  of  Mercury. 

The  true  diameter  of  Venus  is  7700  miles;  but  her  apparent 
diameter  and  brightness  are  constantly  varying,  according  to 
her  distance  from  the  earth.  When  Venus  and  the  earth  are 
on  the  same  side  of  the  sun,  her  distance  from  the  earth  is  only 
26,000,000  of  miles;  when  they  are  on  opposite  sides  of  the 
sun,  her  distance  is  164,000,000  of  miles.  Were  the  whole  of 
her  enlightened  hemisphere  turned  towards  us,  when  she  is 
nearest,  she  would  exhibit  a  light  and  brilliancy  twenty-five 
times  greater  than  she  generally  does,  and  appear  like  a  small 
brilliant  moon ;  but,  at  that  time,  her  dark  hemisphere  is  turned 
towards  the  earth. 

When  Venus  approaches  nearest  to  the  earth,  her  apparent  or 
observed  diameter,  is  6L".2  ;  when  most  remote  it  is  only  9".6  :  now 
61".2-f-9".6=6f.  hence  when  nearest  the  earth,  her  apparent  diameter 
is  6|  times  greater  than  when  most  distant,  and  the  surface  of  her  disk 
(6§)2  or  nearly  41  times  greater.  In  this  work,  the  apparent  size  of  the 
heavenly  bodies  is  estimated  from  the  apparent  surface  of  their  disks,  which 
is  always  proportional  to  the  squares  of  their  apparent  diameters. 

When  Venus's  right  ascension  is  less  than  that  of  the  sun,  she 
rises  before  him;  when  greater,  she  appears  after  his  setting. 
She  continues  alternately  morning  and  evening  star,  for  a 
period  of  292  days,  each  time. 

To  those  who  are  but  little  acquainted  with  astronomy,  it  will 
seem  strange,  at  first,  that  Venus  should  apparently  continue 
longer  on  the  east  or  west  side  of  the  sun,  than  the  whole  time 


VENUS. 


231 


of  her  periodical  revolution  around  him.  But  it  maybe  easily 
understood,  when  it  is  considered,  that  while  Venus  movea 
around  the  sun,  at  the  rate  of  about  1°  36'  of  angular  motion 
per  day,  the  earth  follows  at  the  rate  of  59';  so  that  Venus 
actually  gains  on  the  earth,  only  37'  in  a  day. 

Now  it  is  evident  that  both  planets  will  appear  to  keep  on 
the  same  side  of  the  sun,  until  Venus  has  gained  half  her  orbit, 
or  180°  in  advance  of  the  earth;  and  this  at  a  mean  rate,  will 
require  292  days,  since,  292x37'=10804',  or  180°  nearly. 

Mercury  and  Venus  are  called  Inferior*  planets,  because 
their  orbits  are  within  the  earth's  orbit,  or  between  it  and  the 
sun.  The  other  planets  are  denominated  Superior,  because  their 
orbits  are  without  or  beyond  the  orbit  of  the  earth.  As  the 
orbits  of  Mercury  and  Venus  lie  within  the  earth's  orbit,  it  is 
plain,  that  once  in  every  synodical  revolution,  each  of  these 
planets  will  be  in  conjunction  on  the  same  side  of  the  sun.  In 
the  former  case,  the  planet  is  said  to  be  in  its  inferior  conjunc- 
tion^ and  in  the  latter  case,  in  its  superior  conjunction;  as  in  the 
following  figure. 


CONJUNCTION    AND    OPPOSITION    OF    THE.  PLANETS. 


*ln  almost  all  works  on  astronomy.  Mercury  and  Venus  are  denominated 
inferior  planets,  snd  the  others  superior.  But  as  these  terms  are  employed, 
not  to  express  the  relative  size  of  the  planets,  but  ID  indicate  their  situation 
with  respect  to  the  tfarth,  it  would  be  better  to  adopt  the  terms  interior  aud 
exterior. 


232  GEOGRAPHY   OF   THE  HEAVENS. 

The  period  of  Venus's  sy nodical  revolution,  is  found  in  the  same  man- 
ner as  that  of  Mercury  ;  namely,  by  dividing  the  whole  circumlerence  of 
her  orbit  by  her  mean  relative  motion  in  a  day.  Thus,  Venus's  absolute 
mean  daily  motion,  is  1°  36'  7".8,  the  earth's  is  59'  8".3,  and  their 
difference  36'  59".5.  Divide  360°  by  36'  59".5,  and  it  gives  68.J.92U  ; 
or  nearly  584  days,  for  Venus's  synodical  revolution,  or  the  period  in 
which  she  is  twice  in  conjunction  with  the  earth. 

Venus  passes  from  her  inferior  to  her  superior  conjunction  in 
about  292  days.  At  her  inferior  conjunction,  she  is  26,000,000  of 
miles  from  the  earth;  at  her  superior  conjunction,  164,000.000 
of  miles. 

It  might  be  expected  that  her  brilliancy  would  be  proportion- 
ally increased,  in  the  one  case,  and  diminished,  in  the  other;  and 
so  it  would  be,  were  it  not  that  her  enlightened  hemisphere  is 
turned  more  and  more  from  us,  as  she  approaches  the  earth,  and 
comes  more  and  more  into  view  as  she  recedes  from  it.  It  is  to 
this  cause  alone  that  we  must  attribute  the  uniformity  of  her 
splendor  as  it  usually  appears  to  the  naked  eye. 

Mercury  and  Venus  present  to  us,  successively,  the  various 
shapes  and  appearances  of  the  moon;  waxing  and  waning 
through  different  phases,  from  the  beautiful  crescent  to  the  full 
rounded  orb.  This  fact  shows,  that  they  revolve  around  the 
sun,  and  between  the  sun  and  the  earth.  Let  the  pupil  endeavor 
to  explain  these  phases  on  any  other  supposition,  and  he  will  be 
convinced  that  the  system  of  Ptolemy  is  erroneous,  while  that 
of  Copernicus  is  confirmed. 

It  should  be  remarked,  however,  that  Venus  is  never  seen  when  she  is 
entirely  full,  except  once  or  twice  in  a  century,  when  she  passes  directly 
over  the  sun's  disk.  At  every  other  conjunction,  she  is  either  behind  the 
sun,  or  so  near  him  as  to  be  hidden  by  the  splendor  of  his  light. 

From  her  inferior  to  her  superior  conjunction,  Venus  appears 
on  the  west  side  of  the  sun,  and  is  then  our  morning  star ;  from 
her  superior  to  her  inferior  conjunction  she  appears  on  the  east 
side  of  the  sun,  and  is  then  our  evening  star. 

Like  Mercury,  she  sometimes  seems  to  be  stationary.  Her 
apparent  motion,  like  his,  is  sometimes  rapid  ;  at  one  time, 
direct,  and  at  another,  retrograde;  vibrating  alternately  back- 
wards and  forwards,  from  west  to  east,  and  from  east  to  west. 
These  vibrations  appear  to  extend  from  45°  to  47°,  on  each  side 
of  the  sun. 

Consequently  she  never  appears  in  the  eastern  horizon,  more  than 
three  hours  before  sunrise,  nor  continues  longer  in  the  western  horizon, 
after  sunset.  Any  star  or  planet,  therefore,  however  brilliant  it  may  ap- 
pear, which  is  seen  earlier  or  later  than  this,  cannot  be  Venus.  ' 


VENUS. 


233 


In  passing  from  her  western  to  her  eastern  elongation,  her 
motion  is  from  west  to  east,  in  the  order  of  the  signs  ;  it  is  thence 
called  direct  motion.  In  passing  from  her  eastern  to  her  western 
elongation,  her  motion  with  respect  to  the  earth,  is  from  east  to 
we.st,  contrary  to  the  order  of  the  signs  ;  it  is  thence  denominated 
retrograde  motion.  Her  motion  appears  quickest  about  the  time 
of  her  conjunctions,  and  she  seems  stationary,  at  her  elonga- 
tions. She  is  brightest  about  thirty-six  days  before  and  after 
her  inferior  conjunction,  when  her  light  is  so  great  as  to  project 
a  visible  shadow  in  the  night,  and  sometimes  she  is  visible  even 
at  noon-day. 

DIRECT    AND    RETROGRADE    MOTION. 


In  the  foregoing  figure,  the  outer  circle  represents  the  earth's  orbit,  and  the 
inner  circle,  that  of  Venus,  while  she  moves  around  the  sun.  in  the  order  of  the 
letters  a.  b.  e,  rf,  &c.  When  Venus  is  at  a,  she  is  in  her  inferior  conjunction, 
between  the  earth  and  sun  ;  and  is  in  a  situation  similar  to  that  of  the  moon  at 
her  change,  being  then  invisible,  because  her  dark  hemisphere  is  towards  the 
earth.  At  c,  she  appears  half  enlightened  to  the  earth,  like  the  moon  in  her 
first  quarter ;  at  d.  she  appears  almost  full,  her  enlightened  side  being  then 
almost  directly  towards  the  earth  ;  at  e.  she  is  in  her  superior  conjunction,  and 
would  appear  quite  full,  were  she  not  directly  behind  the  sun.  or  so  near  him 
as  to  be  hidden  by  the  splendor  of  his  light;  at/,  she  appears  to  be  on  the  de- 
crease :  and  at  g-,  only  half  enlightened,  like  the  moon  in  her  last  quarter  ;  at  a, 
she  disappears  again  between  the  earth  and  the  sun.  In  moving  from  g  to  «, 
she  seems  to  go  backwards  in  the  heavens,  because  she  moves  contrary  to  the 
order  of  the  signs.  In  turning  the  arc  of  the  circle  from  retrograde  to  direct 
motion,  or  from  direct  to  retrograde,  she  appears  nearly  stationary  for  a  few 
days ;  because,  in  the  former  case,  she  is  going  almost  directly  from  the  earth, 

v2 


234  GEOGRAPHY  OF  THE  HEAVENS. 

and  in  the  latter  coming  towards  it.  As  she  describes  a  much  larger  portion 
of  her  orbit  in  going  from  c  to  g,  than  from  g  to  c.  she  appears  much  longer 
direct  than  retrograde.  At  a  mean  rate,  her  retrogradations  are  accomplished 
in- forty-two  days. 

If  the  orbit  of  Venus  lay  exactly  in  the  plane  of  the  earth's 
orhit,  she  would  pass  centrally  across  the  sun's  disk,  like  a  dark 
round  spot,  at  every  inferior  conjunction ;  but  as  one  half  of  her 
orhit  lies  about  3£°  above  the  ecliptic,  and  the  other  half  as  far 
below  it,  she  will  always  pass  the  sun  a  very  little  above  or 
below  it,  except  when  her  inferior  conjunction  happens  in,  or 
near,  one  of  her  nodes;  in  which  case  she  will  make  a  transit. 

This  phenomenon,  therefore,  is  of  very  rare  occurrence  :  it 
can  happen  only  twice  in  a  century ;  because  it  is  only  twice  in 
that  time  that  any  number  of  complete  revolutions  of  Venus,  are 
just  or  nearly  equal  to  a  certain  number  of  the  earth's  revolutions. 

The  principle  which  was  illustrated  in  predicting  the  transits  of  Mercury 
applies  equally  well  to  those  of  Venus ;  that  is,  we  must  find  such  sets 
of  numbers,  (representing  complete  revolutions  of  the  earth  and  Venus), 
as  shall  be  to  each  other  in  the  ratio  of  their  periodical  times,  or  as  3H5.256 
is  to  <224.7.  Thus;  the  motion  of  Venus,  in  one  Julian  year,  is 
2106591".52,  that  of  the  earth  for  the  same  period  being  U 9627" -45, 
the  ratio  will  be  1 5-^4"- ".f  !•  As  tne  two  terrns  of  this  fraction  cannot 
be  reduced  by  a  common  divisor,  we  must  multiply  them  by  such  num- 
bers as  will  make  one  a  multiple  of  the  other  ;  accordingly,  thirteen  times 
the  denominator  will  be  nearly  equal  to  eight  times  the  numerator  ;  and 
.475  times  the  denominator  will  equal  29 1  times  the  numerator. 

By  combining  these  two  periods  and  their  multiples  by  addition  and 
subtraction,  we  shall  obtain  the  period  of  all  the  transits  that  have  ever 
happened.  Thus:  291 — 8X7=235,  another  period;  and  291—6X8 
=243,  another  period,  and  so  on.  Whence  we  find  that, 

8  periodical  revolutions  of  the  earth,  are  equal  to  13  of  Venus. 

235  periodical  revolutions  of  the  earth,  are  equal  to  382  of  Venus. 

243  periodical  revolutions  of  the  earth,  are  equal  to  395  of  Venus. 

251  periodical  revolutions  of  the  earth,  are  equal  to  408  of  Venus. 

29 1  periodical  revolutions  of  the  earth,  are  equal  to  475  of  Venus. 

Hence  a  transit  of  Venus  may  happen  at  the  same  node,  after  an  in- 
terval of  eight  years  ;  but  if  it  do  not  happen  then,  it  cannot  take  place 
again,  at  the  same  node,  hi  less  than  235  years.  The  orbit  of  Venus 
crosses  the  ecliptic  near  the  middle  of  Gemini  and  Sagittarius ;  and  these 
points  mark  the  position  of  her  nodes.  At  present  her  ascending  node  is 
in  the  14th  degree  of  Gemini,  and  her  descending  node,  in  the  same 
degree  of  Sagittarius. 

The  earth  passes  her  ascending  node  in  the  beginning  of 
December,  and  her  descending  node,  in  the  beginning  of  June. 
Hence,  the  transits  of  Venus,  for  ages  to  come,  will  happen  in 
December  and  June.  The  first  transit  ever  known  to  have  been 
seen  by  any  human  being,  took  place  at  the  ascending  node. 


THE   SOLAR   SYSTEM  235 

December  4th,  1639.*  If  to  this  date,  we  add  235  years,  we 
shall  have  the  time  of  the  next  transit  at  the. same  node,  which 
will  accordingly  happen  in  1874.  There  will  be  another  at  the 
sviine  node  in  1882,  eight  years  afterwards.  It  is  not  more  cer- 
tain that  this  phenomenon  will  recur,  than  that  the  event  itself 
will  engrbss  the  attention  of  all  the  astronomers  then  living 
upon  the  earth.  It  will  be  anticipated,  and  provided  for,  and 
observed,  in  every  inhabited  quarter  of  the  globe,  with  an  in- 
tensity of  solicitude  which  no  natural  phenomenon  since  the 
creation,  has  ever  excited. 

The  reason  why  a  transit  of  Venus  should  excite  so  great  an 
interest,  is,  because  it  may  be  expected  to  solve  an  important 
problem  in  astronomy,  which  has  never  yet  been  satisfactorily 
done: — a  problem  whose  solution  will  make  known  to  us  the 
magnitudes  and  masses  of  all  the  planets,  the  true  dimensions 
of  their  orbits,  their  rates  of  motion  around  the  sun,  and  their 
respective  distances  from  the  sun,  and  from  each  other.  It  may 
be  expected,  in  short,  to  furnish  a  universal  standard  of  astro- 
nomical measure.  Another  consideration  will  render  the  ob- 
servation of  this  transit  peculiarly  favorable ;  and  that  is, 
astronomers  will  be  supplied  with  better  instruments,  and  more 
accurate  means  of  observation,  than  on  any  former  occasion. 

*  This  phenomenon  was  first  witnessed  by  Horrox,  a  young  gentleman  about 
twenty-one  years  of  age,  living  in  an  obscure  village  fifteen  miles  north  of 
Liverpool.  The  tables  of  Kepler,  constructed  upon  the  observations  of  Tycho 
Brahe,  indicated  a  transit  of  Venus  in  1631,  but  none  was  observed.  Horrox, 
without  much  assistance  from  books  and  instruments,  set  himself  to  inquire 
into  the  error  of  the  tables,  and  found  that  such  a  phenomenon  might  be  ex- 
pected  to  happen  in  1639.  He  repeated  his  calculations  during  this  interval, 
with  all  the  carefulness  and  enthusiasm  of  a  scholar  ambitious  of  being  the 
first  to  predict  and  observe  a  celestial  phenomenon,  which,  from  the  creation 
of  the  world,  had  never  been  witnessed.  Confident  of  the  result,  he  communi- 
cated his  expected  triumph  to  a  confidential  friend  residing  in  Manchester,  and 
desired  him  to  watch  for  the  event,  and  to  take  observations.  So  anxious  was 
Horrox  not  to  fail  of  witnessing  it  himself,  that  he  commenced  his  observations 
the  day  before  it  was  expected,  and  resumed  them  at  the  rising  of  the  sun  on 
the  morrow.  But  the  very  hour  when  his  calculations  led  him  to  expect  the 
visible  appearance  of  Venus  upon  the  sun's  disk,  was  also  the  appointed  hour 
for  the  public  worship  of  GOD  on  the  Sabbath.  The  delay  of  a  few  minutes 
might  deprive  him  forever  of  an  opportunity  of  observing  the  transit.  If  its 
very  commencement  were  not  noticed,  clouds  might  intervene,  and  conceal  it  ^ 
until  the  sun  should  set:  and  nearly  a  century  and  a  half  would  elapse  before 
another  opportunity  would  occur.  He  had  been  waiting  for  the  event  with  the 
most  ardent  anticipation  for  eight  years,  and  the  result  promised  much  benefit 
to  ihe  science.  Notwithstanding  all  this,  Horrox  twice  suspended  his  observations, 
and  twice  repaired  to  the  house  of  God,  the  Great  Author  of  the  bright  worlds  he 
delighted  to  contemplate.  When  his  duty  was  thus  performed,  and  he  had 
returned  to  his  chamber  the  second  time,  his  love  of  science  was  gratified  with 
fuil  success;  and  he  saw  what  no  mortal  eye  had  observed  before  ! 

If  any  thing  can  add  interest  to  this  incident,  it  is  the  modesty  with  which 
the  young  astronomer  apologizes  to  the  world,  for  suspending  his  observations 
at  all. 

"  I  observed  it,"  says  he,  "  from  sunrise  till  nine  o'clock,  again  a  little  before 
ten.  and  lastly  at  noon,  and  from  one  to  two  o'clock  ;  the  rest  of  the  day  being 
devoted  to  higher  duties,  which  might  not  be  neglected  for  these  pastimes." 


236  GEOGRAPHY  OF  THE  HEAVENS. 

So  important,  says  Sir  John  Herschel,  have  these  observations  appeared 
to  astronomers,  that  at  the  last  transit  of  Venus,  in  1769,  expeditions  were 
fitted  out,  on  the  most  efficient  scale,  by  the  British,  French,  Russian,  and 
other  governments,  to  the  remotest  corners  of  the  globe,  for  the  express 
purpose  of  making  them.  The  celebrated  expedition  of  Captain  Cook  to 
Otaheite,  was  one  of  them.  The  general  result  of  all  the  observations 
made  on  this  most  memorable  occasion,  gives  fct".5776  for  the  sun's 
horizontal  parallax. 

The  phenomena  of  the  seasons,  of  each  of  the  planets,  like 
those  of  the  earth,  depend  upon  the  inclination  of  the  axis  of 
the  planet,  to  the  plane  of  its  orbit.  The  inclination  of  the  axis 
of  Venus  to  the  plane  of  her  orbit,  though  not  precisely  known, 
is  commonly  estimated  at  75°;  which  is  more  than  three  times 
as  great  as  the  inclination  of  the  earth's  axis  to  the  plane  of  the 
ecliptic.  The  north  pole  of  Venus's  axis  inclines  towards  the 
20th  degree  of  Aquarius  ;  the  earth's  towards  the  beginning  of 
Cancer ;  consequently,  the  northern  parts  of  Venus  have  summer 
in  the  signs  where  those  of  the  earth  have  winter,  and  vice  versa. 

The  declination  of  the  sun  on  each  side  of  her  equator,  must 
be  equal  to  the  inclination  of  her  axis;  and  if  this  extends  to 
75°,  her  tropics  are  only  15°  from  her  poles,  and  her  polar 
circles  15°  from  her  equator.  It  follows,  also,  that  the  sun 
must  change  his  declination  more  in  one  day  at  Venus,  than  in 
five  days  on  the  earth  ;  and  consequently,  that  he  never  shines 
vertically  on  the  same  places  for  two  days  in  succession.  This 
may  perhaps  be  providentially  ordered,  to  prevent  too  great  effect 
of  the  sun's  heat,  which,  on  the  supposition  that  it  is  in  inverse 
proportion  to  the  square  of  the  distance,  is  twice  as  great  on  this 
planet,  as  it  is  on  the  earth. 

At  each  pole,  the  sun  continues  half  a  year  *  without  setting 
in  summer,  and  as  long  without  rising  in  winter;  consequently, 
the  polar  inhabitants  of  Venus,  like  those  of  the  earth,  have  only 
one  day  and  one  night  in  the  year  ;  with  this  difference,  that  the 
polar  days  and  nights  of  Venus  are  not  quite  two-thirds  as  long 
as  ours. 

Between  her  polar  circles,  which  are  but  15°  from  her  equator, 
there  are  two  winters,  two  summers,  two  springs,  and  two 
autumns,  every  year.  But  because  the  sun  stays  for  some  time 
near  the  tropics,  and  passes  so  quickly  over  the  equator,  the 
winters  in  that  zone  will  be  almost  twice  as  long  as  the 
summers. 

When  viewed  through  a  good  telescope,  Venus  exhibits  not 
only  all  the  moon-like  phases  of  Mercury,  but  also  a  variety  of 
inequalities  on  her  surface ;  dark  spots,  and  brilliant  shades, 
hills,  and  valleys,  and  elevated  mountains.  But  on  account  of 

*That  is,  half  of  Venus's  year,  or  sixteen  weeks. 


VENUS.  237 

the  great  density  of  her  atmosphere,  these  inequalities  are  per- 
ceived with  more  difficulty  than  those  upon  the  other  planets. 

The  mountains  of  Venus,  like  those  of  Mercury  and  the  moon, 
are  highest  in  the  southern  hemisphere.  According  to  M. 
Schroeter,  a  celebrated  German  astronomer,  who  spent  more 
than  ten  years  in  observation  upon  this  planet,  some  of  hei 
mountains  rise  to  the  enormous  hight  of  from  ten  to  twenty-two 
miles.*  The  observations  of  Dr.  Herschel  do  not  indicate  so 
great  an  altitude ;  and  he  thinks,  that  in  general  they  are  con- 
siderably overrated.  He  estimates  the  diameter  of  Venus  at 
8,649  miles  ;  making  her  bulk  more  than  one-sixth  larger  than 
that  of  the  earth.  Several  eminent  astronomers  affirm,  that  they 
have  repeatedly  seen  Venus  attended  by  a  satellite,  and  they 
have  given  circumstantial  details  of  its  size  and  appearance,  its 
periodical  revolution  and  its  distance  from  her.  It  is  said  to  re- 
semble our  moon  in  its  phases,  its  distance,  and  its  magnitude. 
Other  astronomers  deny  the  existence  of  such  a  body,  because 
it  was  not  seen  with  Venus  on  the  sun's  disk,  at  the  transits  of 
1761,  and  1769.  t 

The  general  elements  of  this  planet  for  the  epoch  1st  January, 
1801,  are  as  follows  : 

Mean  sidereal  revolution,         -  -      224  d.  16  h.  49  m.  OSs.OO 

Mean  synodical  revolution  in  solar  days,    -  583.92 

Mean  longitude,  -  -  11°  33'  03".c<0 

Mean  daily  motion  in  orbit,  -  -  -        1    36  07  .80 

Longitude  of  perihelion,  -         .;^,rj      128    4353.10 

W.  motion  of  apsides  per  annum,  -  -  -       02  .70 

E.  «  "      referred  to  the  ecliptic,  47  .40 

Inclination  of  orbit,  -  -  -  3    23  28  .5 

Annual  increase  of  do.,  -  -    •         •  00    5 

Longitude  of  ascending  node,        ?•',.          -    ;        -      74    54   12  .9 
W.  motion  of  do.  per  annum,  -        •,  *rij  .        -  17  .6 

E.      .  "  "      referred  to  the  ecliptic,   -  -  -      32  .5 

Eccentricity  of  orbit  half  maj.  axis  as  unity,    -  -    0.00^86074 

Decrease  of  do.  in  a  century,     . ' .' '  - . ' :        '-  -         0.0000f>27 1 1 

Greatest  equation  of  center,     -  47'  l.V'.OO 

Annual  decrease  of  do.,      -        (   ><•  '.,         -  -  -      00  .25 

Rotation  on  axis,      '  _«j; ;    '. '../•„.,...        •  23  h.  21  m.  07s.2 

Mean  apparent  diameter,  -  -  -  -      16",9 

Diameter  at  superior  conjunction,         -  -  -  0°  .6 

Diameter  at  inferior  conjunction.  -  -  -  1'  0 '  ".2 

True  diameter  (7700  miles)  earth's  as  unity,  -  -  0  97* 

Volume  earth's  as  unity,  -----        0.92? 
Mass  sun's  as  unity,    -  -  -  0.00000246:^ 

Mean  distance  from  the  sun,  (68,000,000  miles),  earth's  ?  ()  723;?3i6 
as  unity.  5 

« 1st,  22.05  miles ;  2d,  18.97  miles;  3d,  11.44  miles  j  4th.  10.84  miles. 


238  GEOGRAPHY  OF  THE  HEAVENS. 


THE  EARTH. 

THE  earth  is  the  place  from  which  all  our  observations  of  the 
heavenly  bodies  must  necessarily  be  made.  The  apparent  mo- 
tions of  these  bodies  being:  very  considerably  affected  by  her 
figure,  motions,  and  dimensions,  these  hold  an  important  place 
in  astronomical  science.  It  will,  therefore,  be  proper  to  consider, 
first,  some  of  the  methods  by  which  they  have  been  determined. 

If,  standing  on  the  sea-shore,  in  a  clear  day,  we  view  a  ship 
leaving  the  coast,  in  any  direction,  the  hull,  or  body  of  the  ves- 
sel, first  disappears  ;  afterward  the  rigging,  and,  lastly,  the  top 
of  the  mast  vanishes  from  our  sight.  Those  on  board  the  ship 
observe  that  the  coast  first  sinks  below  the  horizon,  then  the 
buildings,  and.  lastly,  the  tallest  spires  of  the  city,  which  they 
are  leaving.  Now  these  phenomena  are  evidently  caused  by 
the  convexity  of  the  water  which  is  between  the  eye  and  the 
object;  for,  were  the  surface  of  the  sea  merely  an  extended 
plain,  the  largest  objects  would  be  visible  the  longest,  and  the 
smallest  disappear  first. 

Again,  navigators  have  sailed  quite  around  the  earth,  and  thus 
proved  its  convexity. 

Ferdinand  Magellan,  a  Portuguese,  was  the  first  who  carried  this  en- 
terprise into  execution.  He  embarked  from  Seville,  in  Spain,  and  direc- 
ted his  course  toward  the  west.  After  a  long  voyage,  he  descried  the 
continent  of  America.  Not  finding  an  opening  to  enable  him  to  continue 
his  course  in  a  westerly  direction,  he  sailed  along  the  coast  toward  the 
south,  until,  coming  to  its  southern  extremity,  he  sailed  around  it,  and 
found  himself  in  the  great'Southern  Ocean.  He  then  resumed  his  course 
toward  the  west.  After  some  time,  he  arrived  at  the  Molucca  Islands,  in 
the  Eastern  Hemisphere,-  and,  sailing  continually  toward  the  west,  he 
made  Europe  from  the  east, — arriving  at  the  place  from  which  he  set  out.* 

The  next  who  circumnavigated  the  earth,  was  Sir  Francis  Drake,  who 
sailed  from  Plymouth,  December  13,  1577,  with  five  small  vessels,  and 
arrived  at  the  same  place,  September  26,  1580.  Since  that  time,  the 
circumnavigation  of  the  earth  has  been  performed  by  <  'avendish,  Cordes, 
Noort,  Sharten,  Heremites,  Dampier,  Woodes,  Rogers,  Schovten,  Rogge- 
win,  Lord  Anson,  Byron,  Carteret,  Wallis,  Bougainville,  Cook,  King, 
Clerk,  Vancouver,  and  many  others. 

*  Magellan  sailed  from  Seville,  in  Spain,  August  10,  1519,  in  a  ship  called  the 
Victory,  accompanied  by  four  other  vessels.  In  April.  1521,  he  was  killed  in 
a  skirmish  with  the  natives,  at  the  island  of  Sebu.  or  Zebu,  sometimes  called 
Matan.  one  of  the  Philippines.  One  of  his  vessels,  however,  arrived  at  St. 
J  ucar.  near  Seville.  Septeml>ftr  7. 1522. 


THE  EARTH. 

These  navigators,  by  sailing  in  a  westerly  direction,  allow- 
ance being  made  for  promontories,  &c.,  arrived  at  the  country 
they  sailed  from.  Hence,  the  earth  must  be  either  cylindrical 
or  globular.  It  cannot  be  cylindrical,  because,  if  so,  the  meri- 
dian distances  would  all  be  equal  to  each  other,  which  is  con- 
trary to  observation.  The  figure  of  the  earth  is,  therefore, 
spherical. 

The  convexity  of  the  earth,  north  and  south,  is  proved  by  the 
altitude  of  the  pole,  and  of  the  circumpolar  stars,  which  is 
found  uniformly  to  increase  as  we  approach  them,  while  the  in- 
clination to  the  horizon,  of  the  circles  described  by  all  the  stars, 
gradually  diminishes.  While  proceeding  in  a  southerly  direc- 
tion, the  reverse  of  this  takes  place.  The  altitude  of  the  pole, 
and  of  the  circumpolar  stars,  continually  decreases;  and  all  the 
stars  describe  circles  whose  inclination  to  the  horizon  increases 
with  the  distance.  Whence  we  derive  this  general  truth :  The 
altitude  of  one  pole,  and  the  depression  of  the  other ,  at  any  place  on 
the  earth's  surface,  is  equal  to  the  latitude  of  that  place. 

Another  proof  of  the  convexity  of  the  earth's  surface  is,  that 
the  higher  the  eye  is  raised,  the  further  is  the  view  extended. 
An  observer  may  see  the  setting  sun  from  the  top  of  a  house,  or 
any  considerable  eminence,  after  he  has  ceased  to  be  visible  to 
those  below. 

The  curvature  of  the  earth  for  one  mile  is  eight  inches ;  and  this  cur- 
vature increases  with  the  square  of  the  distance.  From  this  general  law, 
it  will  be  easy  to  calculate  the  distance  at  which  any  object,  whose  hight 
is  given,  may  be  seen,  or  to  determine  the  hight  of  an  object,  when  the 
distance  is  known. 

1 .  To  find  the  hight  of  an  object  when  the  distance  is  given. 
RULE.   Find  the  square  of  the  distance  in  miles,  and  take  two-thirds 

of  that  number  for  the  hignt  in  feet.  . 

Ex.  I.  How  high  must  the  eye  of  an  observer  be  raised,  to  see  the 
surface  of  the  ocean,  at  the  distance  of  3  miles  1  Ans.  The  square  of  3 
feet  is  9  feet,  and  $  of  9  feet  is  6  feet. 

Ex.  2.  Suppose  a  person  can  just  see  the  top  of  a  spire,  over  an  ex- 
tended plain  of  10  miles,  how  high  is  the  steeple?  Ans.  The  square  of 
10  is  100,  and  #  of  100  is  66$  feet. 

2.  To  find  the  distance  when  the  hight  is  given. 

RULE.  Increase  the  hight  in  feet  one-half,  and  extract  the  square  root, 
for  the  distance,  in  miles. 

Ex.  1.  How  far  can  a  person  see  the  surface  of  a  plain,  whose  eye  is 
elevated  6  feet  above  it?  Ans.  6,  increased  by  its  half,  is  9,  and  the 
square  root  of  9  is  3  :  the  distance  is,  then,  3  miles, 

Ex.  2.  To  what  distance  can  a  person  see  a  lighthouse  whose  hight  is 
96  feet  from  the  level  of  the  ocean  ?  Ans.  96,  increased  by  its  half,  is 
144,  and  the  square  root  of  144  is  12 :  the  distance  is,  therefore,  12  miles. 

3.  To  find  the  curvature  of  the  earth  when  it  exceeds  a  mile. 
RULE.  Multiply  the  square  of  the  distance  by  .000126. 


240 


GEOGRAPHY  OF  THE  HEAVENS. 


Places  of 
Observation. 
Peru, 
Pennsylvania, 
Italy, 
France, 
England, 
Sweden. 

Latitude. 
Equator 
390  12'  00"  N. 
43    01  00 
46    00  00 
51    29  54£ 
66    20   10 

Length  of  a  degree 
in  English  miles,  i 
68.732 
68.896 
68.998 
69.054 
69.146 
69.292 

Although  it  appears,  from  the  preceding  facts,  that  the  earth 
is  spherical,  yet  it  is  not  a  perfect  sphere.  If  it  were,  the  length 
of  the  degrees  of  latitude,  from  the  equator  to  the  poles,  would 
be  uniformly  the  same ;  but  it  has  been  found,  by  the  most  care- 
ful measurement,  that,  as  we  go  from  the  equator  toward  the 
poles,  the  length  increases  with  the  latitude. 

These  measurements  have  been  made  by  the  most  eminent  mathema- 
ticians of  different  countries,  and  in  various  places,  from  the  equator  to 
the  arctic  circle.  They  have  found  that  a  degree  of  latitude  at  the  arctic 
circle  was  nine  sixtetntlia  of  a  mile  longer  than  a  degree  at  the  equator, 
and  that  the  ratio  of  increase,  for  the  intermediate  degrees,  was  nearly  as 
the  squares  of  the  sines  of  the  latitude.  Thus  the  theory  of  Sir  Isaac 
Newton  was  confirmed,  that  the  body  of  the  earth  was  more  rounded 
and  convex  between  the  tropics,  but  considerably  flattened  toward  the 
poles. 

ires  of        I  Leneth  of  a  desree 

Observers. 
Bouguer, 

Mason  and  Dixon, 
Boscovich  and  Lemaire 
Delambre  and  Mechain 
Mudge, 
Swamberg. 

These  measurements  prove  the  earth  to  be  an  oblate  spheroid, 
whose  longest  or  equatorial  diameter  is  7924  miles,  and  the  po- 
lar diameter,  7898  miles.  The  mean  diameter  is,  therefore, 
about  7911,  and  their  difference  26  miles.  The  French  Academy 
have  determined  that  the  mean  diameter  of  the  earth,  from  the 
45th  degree  of  north  latitude,  to  the  opposite  degree  of  south  la- 
titude, is,  accurately^  7912  miles. 

If  the  earth  were  an  exact  sphere,  its  diameter  might 
be  determined  by  its  curvature,  from  a  single  measure- 
ment. Thus,  in  the  adjoining  figure,  we  have  A  B  equal 
to  1  mile,  and  B  D  equal  to  8  inches,  to  find  A  E,  or  B  K. 
which  does  not  sensibly  differ  from  A  E,  since  B  D  is 
only  8  inches.  Now,  it  is  a  proposition  of  Euclid,  (B.  3, 
prop.  36,)  that,  when,  from  a  point  without  a  circle,  two 
lines  be  drawn,  one  cutting  and  the  other  touching  it,  the 
touching  line  (B  A)  is  a  mean  proportional  between  the 
cutting  line  (B  E)  and  that  part  of  it  (B  D)  without  the 
circle. 

B  D":  B  A  : :  B  A  :  B  E  or  A  E  very  nearly. 

That  is.  1  mile  being  equal  to  63360  inches. 

8  :  63360  :  :  63360  :  50181 1'20  inches,  or  7920  miles. 

This  is  very  nearly  what  the  most  elaborate  calculations  make  the 
earth's  equatorial  diameter. 

The  earth,  considered  as  a  planet,  occupies  a  favored  rank  in 
the  solar  system.  It  pleased  the  all  wise  Creator  to  assign  its 
position  among  the  heavenly  bodies  where  nearly  all  the  sister 
planets  are  visible  to  the  naked  eye.  It  is  situated  next  to 
Venus,  and  is  the  third  planet  from  the  sunk 


THE  EARTH.  241 

To  the  scholar  who,  for  the  first  time,  takes  up  a  book  on  astronomy, 
it  will  no  doubt  seem  strange  to  find  the  earth  classed  with  the  heavenly 
bodies.  For  what  can  appear  more  unlike  than  the  earth,  with  her  vast 
and  seemingly  immeasurable  extent,  and  the  stars,  which  appear  but  as 
points'?  The  earth  is  dark  and  opake;  the  celestial  bodies  are  brilliant 
We  perceive  in  it  no  motion,  while  in  them  we  observe  a  continual 
change  of  place,  as  we  view  them  at  different  hours  of  the  day  or  night, 
or  at  different  seasons  of  the  year. 

It  moves  round  the  sun,  from  west  to  east,  in  365  days,  5 
hours,  48  minutes,  and  48  seconds ;  and  turns,  the  same  way, 
on  its  axis,  in  23  hours,  56  minutes,  and  4  seconds.  The  former 
is  called  its  annual  motion,  and  causes  the  vicissitudes  of  the 
seasons.  The  latter  is  called  its  diurnal  motion,  and  produces 
the  succession  of  day  and  night. 

The  earth's  meari  distance  from  the  sun  is  about  95,000,000 
of  miles ;  it,  consequently,  moves  in  its  orbit  at  the  mean  rate  of 
68,000  miles  an  hour.  Its  equatorial  diameter  being  7924 
miles,  it  turns  on  its  axis  at  the  rate  of  1040  miles  an  hour. 

Thus,  the  earth,  on  which  we  stand,  and  which  has  served 
for  ages  as  the  unshaken  foundation  of  the  firmest  structures,  is 
every  moment  turning  swiftly  on  its  center,  and,  at  the  same 
time,  moving  onward  with  great  rapidity  through  the  empty 
,space. 

This  compound  motion  is  to  be  understood  of  the  whole  earth, 
with  all  that;it  holds  within  its  substance,  or  sustains  upon  its 
surface — of  the  solid  mass  beneath,  of  the  ocean  which  flows 
around  it,  of  the  air  that  rests  upon  it,  and  of  the  clouds  which 
float  above  it  in  the  air. 

That  the  earth,  in  common  with  all  the  planets,  revolves 
around  the  sun  as  a  center,  is  a  fact  which  rests  upon  the  clear- 
est demonstrations  of  philosophy.  That  it  revolves,  like  them, 
upon  its  own  axis,  is  a  truth  which  every  rising  and  setting  sun 
illustrates,  and  which  very  many  phenomena  concur  to  establish. 
Either  the  earth  moves  around  its  axis  every  day,  or  the  whole 
universe  moves  around  it  in  the  same  time.  There  is  no  third 
opinion  that  can  be  formed  on  this  point.  Either  the  earth  must 
revolve  on  its  axis  every  24  hours,  to  produce  the  alternate  suc- 
cession of  day  and  night,  or  the  sun,  moon,  planets,  comets, 
fixed  stars,  and  the  whole  frame  of  the  universe  itself,  must 
move  around  the  earth,  in  the  same  time.  To  suppose  the 
latter  case  to  be  the  fact,  would  be  to  cast  a  reflection  on  the 
wisdom  of  the  Supreme  Architect,  whose  laws  are  universal 
harmony.  As  well  might  the  beetle,  that  in  a  moment  turns  on 
its  ball,  imagine  the  heavens  and  the  earth  had  made  a  revolu- 
tion in  the  same  instant.  It  is  evident,  that  in  proportion  to  the 
distance  of  the  celestial  bodies  from  the  earth,  must,  on  this 
supposition,  be  the  rapidity  of  their  movements.  The  sun,  then, 
W 


242  GEOGRAPHY  OF  THE   HEAVENS. 

would  move  at  the  rate  of  more  than  four  hundred  thousand  miles 
in  a  minute;  the  nearest  stars,  at  the  inconceivable  velocity  of 
fourteen  hundred  millions  of  miles  in  a  second,-  and  the  most 
distant  luminaries,  with  a  degree  of  swiftness  which  no  numbers 
could  express, — and  all  this  to  save  the  little  globe  we  tread 
upon  from  turning  safely  on  its  axis  once  in  24  hours. 

The  idea  of  the  heavens  revolving  about  the  earth,  is  encum- 
bered with  innumerable  other  difficulties.  We  will  mention 
only  one  more.  It  is  estimated  un  good  authority,  that  there 
are  visible,  by  means  of  glasses,  no  less  than  one  hundred 
millions  of  stars,  scattered  at  all  possible  distances  in  the  heavens 
above,  beneath,  and  around  us.  Now,  is  it  in  the  least  degree 
probable,  that  the  velocities  of  all  these  bodies  should  be  so 
regulated,  that,  though  describing  circles  so  very  different  in 
dimensions,  they  should  complete  their  revolutions  in  exactly 
the  same  time? 

In  short,  there  is  no  more  reason  to  suppose  that  the  heavens 
revolve  around  the  earth,  than  there  is  to  suppose  that  they 
revolve  around  each  of  the  other  planets,  separately,  and  at  the 
same  time ;  since  the  same  apparent  revolution  is  common  to 
them  all,  for  they  all  appear  to  revolve  upon  their  axes,  in 
different  periods. 

The  rotation  of  the  earth  determines  the  length  of  the  day, 
and  may  be  regarded  as  one  of  the  most  important  elements  in 
astronomical  science.  It  serves  as  a  universal  measure  of  time, 
and  forms  the  standard  of  comparison  for  the  revolution  of  the 
celestial  bodies,  for  all  ages,  past  and  to  come.  Theory  and 
observation  concur  in  proving,  that  among  the  innumerable 
vicissitudes  that  prevail  throughout  creation,  the  period  of  the 
earth's  diurnal  rotation  is  immutable. 

The  earth  performs  one  complete  revolution  on  its  axis  in 
23  hours,  56  minutes,  and  4.09  seconds,  of  solar  time.  This  is 
called  a  sidereal  day,  because,  in  that  time,  the  stars  appear  to 
complete  one  revolution  around  the  earth. 

But  as  the  earth  advances  almost  a  degree  eastward  in  its 
orbit,  in  the  time  that  it  turns  eastward  around  its  axis,  it  is 
plain  that  just  one  rotation  never  brings  the  same  meridian 
around  from  the  sun  to  the  sun  again;  so  that  the  earth  re- 
quires as  much  more  than  one  complete  revolution  on  its  axis  to 
complete  a  solar  day,  as  it  has  gone  forward  in  that  time. 
Hence  in  every  natural  or  solar  day,  the  earth  performs  one 
complete  revolution  on  its  axis,  and  the  365th  part  of  another 
revolution.  Consequently,  in  365  days,  the  earth  turns  366 
times  around  its  axis.  And  as  every  revolution  of  the  earth  on 
its  axis  completes  a  sidereal  day,  there  must  be  366  sidereal 
days  in  a  year.  And,  generally,  since  the  rotation  of  any  planet 
about  its  axis  is  the  length  of  a  sidereal  day  at  that  planet,  the 


THE   EARTH.  243 

number  of  sidereal  days  will  always  exceed  the  number  of  solar 
days,  by  one,  let  that  number  be  what  it  may,  one  revolution 
beinij  lost  in  the  course  of  an  annual  revolution.  This  difference 
between  the  sidereal  and  solar  days  may  be  illustrated  by 
referring  to  a  watch  or  clock.  When  both  hands  set  out  to- 
gether, at  12  o'clock  for  instance,  the  minute  hand  must  travel 
more  than  a  whole  circle  before  it  wiH  overtake  the  hour  hand, 
that  is,  before  they  will  come  into  conjunction  again. 

In  the  same  manner,  if  a  man  travel  around  the  earth  east- 
wardly,  no  matter  in  what  time,  he  will  reckon  one  day  more, 
on  his  arrival  at  the  place  whence  he  set  out,  than  they  do  who 
remain  at  rest;  while  the  man  who  travels  around  the  earth 
westwardly  will  have  one  day  less.  From  which  it  is  manifest, 
that,  if  two  persons  start  from  the  same  place  at  the  same  time, 
but  go  in  contrary  directions,  the  one  traveling  eastward  and  the 
other  westward,  and  each  goes  completely  around  the  globe, 
although  they  should  both  arrive  again  at  the  very  same  hour 
at  the  same  place  from  which  they  set  out,  yet  they  will  disa- 
gree two  whole  days  in  their  reckoning.  Should  the  day  of 
their  return,  to  the  man  who  traveled  westwardly,  be  Monday, 
to  the  man  who  traveled  eastwardly,  it  would  be  Wednesday ; 
while  to  those  who  remained  at  the  place  itself,  it  would  be 
Tuesday. 

Nor  is  it  necessary,  in  order  to  produce  the  gain  or  loss  of  a 
day,  that  the  journey  be  performed  either  on  the  equator,  or  on 
any  parallel  of  latitude;  it  is  sufficient  for  the  purpose,  that  all 
the  meridians  of  the  earth  be  passed  through,  eastward  or  west- 
ward. The  time,  also,  occupied  in  the  journey,  is  equally 
unimportant;  the  gain  or  loss  of  a  day  being  the  same,  whether 
the  earth  be  traveled  around  in  24  years,  or  in  as  many  hours. 

It  is  also  evident,  that  if  the  earth  turned  around  its  axis 
but  once  in  a  year,  and  if  the  revolution  was  performed  the 
same  way  as  its  revolution  around  the  sun,  there  would  be  per- 
petual day  on  one  side  of  it,  and  perpetual  night  on  the  other. 

From  these  facts  the  pupil  will  readily  comprehend  the  principles  in- 
volved in  a  curious  problem  which  appeared  a  few  years  ago :  It  was 
gravely  reported  by  an  American  ship,  that,  in  sailing  over  the  ocean,  it 
chanced  to  find  six  Sundays  in  February.  The  fact  was  insisted  on, 
and  a  solution  demanded.  There  is  nothing  absurd  in  this. — The  man 
who  travels  around  the  earth,  eastwardly,  will  see  the  sun  go  down  a 
little  earlier  every  succeeding  day,  than  if  he  had  remained  at  rest ;  or 
earlier  than  they  do  who  live  at  the  place  from  which  he  set  out.  The 
faster  he  travels  toward  the  rising  sun,  the  sooner  will  it  appear  above  the 
horizon  in  the  morning,  so  much  the  sooner  will  it  set  in  the  evening. 
What  he  thus  gains  in  time,  will  bear  the  same  proportion  to  a  solar  day, 
as  the  distance  traveled  does  to  the  circumference  of  the  earth. — As  the 
globe  is  360°  in  circumference,  the  sun  will  appear  to  move  over  one 


244  GEOGRAPHY  OF  THE  HEAVENS. 

twenty-fourth  part  of  its  surface,  or  14°  every  hour,  which  is  four 
minutes  to  one  degree* — Consequently,  the  sun  will  rise,  come  to  the 
meridian,  and  set,  four  minutes  sooner,  at  a  place  1°  east  of  us,  than  it 
will  with  us ;  at  the  distance  of  2°,  the  sun  will  rise  and  set  eight  min- 
utes sooner ;  at  the  distance  of  3°,  twelve  minutes  sooner,  and  so  on. 

Now  the  man  who  travels  one  degree  to  the  east,  the  first  day,  will 
have  the  sun  on  his  meridian  four  minutes  sooner  than  we  do  who  are 
at  rest;  and  the  second  day,  eight  minutes  sooner,  and  on  the  third  day, 
twelve  minutes  sooner,  and  so  on ;  each  successive  day  being  complett  d 
four  minutes  earlier  than  the  preceding,  until  he  arrives  again  at  the 
place  from  which  he  started  ;  when  this  continual  gain  of  four  minutoa 
a  day  will  have  amounted  to  a  whole  day  in  advance  of  our  time ;  he 
having  seen  the  sun  rise  and  set  once  more  than  we  have.  Consequently, 
the  day  on  which  he  arrives  at  home,  whatt-vtT  day  of  the  week  it  may 
be,  is  one  day  in  advance  of  ours,  and  he  must  needs  live  that  day  over 
again,  by  calling  that  day  by  the  same  name,  in  order  to  make  the 
accounts  harmonize. 

If  this  should  be  the  last  day  of  February  in  a  bissextile  year,  it  would 
also  he  the  same  day  of  the  week  that  the  first  was,  and  be  six  times 
repeated  ;  and  if  it  should  happen  on  Sunday,  he  would,  under  these 
circumstances,  have  six  Sundays  in  February. 

Again  : — Whereas  the  man  who  travels  at  the  rate  of  one  degree  to  the 
east,  will  have  all  his  days  four  minutes  shorter  than  ours,  s<>,  on  the 
contrary,  the  man  who  travels  at  the  same  rate  toward  the  west,  will 
have  all  his  days  four  minutes  longer  than  ours.  When  he  has  finished 
the  circuit  of  the  earth  and  arrived  at  the  place  from  which  he  first  set 
out,  he  will  have  seen  the  sun  rise  and  set  once  less  than  we  have. 
Consequently,  the  day  he  gets  home  will  be  one  day  after  the  time  of 
that  place  :  for  which  reason,  if  he  arrives  at  home  on  Saturday,  accord- 
ing to  his  own  account,  he  will  have  to  call  the  next  day  Monday ; 
Sunday  having  gone  by  before  he  reached  home.  Thus,  on  whatever 
day  of  the  week  January  should  end,  hi  common  years,  he  would  find 
the  same  day  repeated  only  three  times  in  February.  If  January  ended 
on  Sunday,  he  would,  under  these  circumstances,  find  only  three  Sun- 
days in  February. 

The  earth's  motion  about  its  axis  being  perfectly  equable  and 
uniform  in  every  part  of  its  annual  revolution,  the  sidereal  days 
are  always  of  the  same  length,  but  the  solar  or  natural  days 
rary  very  considerably  at  different  times  of  the  year.  This 
variation  is  owing  to  two  distinct  causes:  the  inclination  of  the 
earth's  axis  to  its  orbit,  and  the  inequality  of  its  motion  around 
*he  sun.  From  these  two  causes  it  is,  that  the  time  shown  by 
A  well  regulated  clock,  and  that  of  a  true  sun-dial,  are  scarcely 
*ver  the  same.  The  difference  between  them,  which  sometimes 
amounts  to  16^  minutes,  is  called  the  Equation  of  Time,  or  the 
venation  of  solar  days. 

The  difference  between  mean  and  apparent  time,  or,  hi  other  words, 
Between  Equinoctial  and  Ecliptic  time,  may  be  further  shown  by  the 


THE   EARTH. 


245 


figure  which  represents  the  circle  of  the  sphere.  Let  it  be  first  prerrrsed, 
that  equinoctial  time  is  clock  time]  and  that  ecliptic  time  is  .War  or 
apparent  time.  It  appears  that  from  Aries  to  Cancer,  the  sun  in  the 
ecliptic  comes  to  the  meridian  before  the  equinoctial  snn  ;  from  Cancer 
to  Libra,  after  it ;  from  Libra  to  Capricorn  before  it ;  and  from  Capricorn 
to  Aries,  after  it.  If  we  notice  what  months  the  sun  is  in  these  several 
quarters,  we  shall  find  that  from  the  25th  of  December  to  the  16th  of 
April,  and  from  the  16th  of  June  to  the  1st  of  September,  th.e  clock  is 
faster  than  the  sun-dial;  and  that,  from  the  iHth  of  April  to  the  1 6th  of 
June,  and  from  the  1st  of  September  to  the  25th  of  December,  the  sun- 
dial is  faster  than  the  clock. 


EQUATION    OF    TIME. 
K 


It  is  a  universal  fact,  that,  while  none  of  the  planets  are 
perfect  spheres,  none  of  their  orbits  are  perfect  circles.  The 
planets  all  revolve  about  the  sun,  in  ellipses  of  different  degrees 
of  eccentricity ;  having  the  sun,  not  in  the  center  of  the  ellipse, 
I -lit  in  one  of  its  foci. 


The  figure  A  D  B  E  is  an  ellipse.  The  line 
A  B  is  called  the  transverse  axis,  and  the 
line  drawn  through  the  middle  of  this  line, 
and  perpendicular  to  it,  is  the  conjugate 
axis.  The  point  C,  the  middle  of  the  trans- 
verse axis,  is  the  center  of  the  ellipse.  The 
points  F  and  f,  equally  distant  from  C,  are 
called  the/oci.  C  F,  the  distance  from  the 
center  to  one  of  the  foci,  is  called  the  eccen- 
tricity. The  orbits  of  the  planets  being  el- 
lipses, having  the  sun  in  one  of  the  foci,  if 
A  B  D  E  be  the  orbit  of  a  planet,  with  the 
sun  in  the  focus  F,  when  the  planet  is  at 


246  GEOGRAPHY  OF  THE  HEAVENS. 

the  point  A,  it  will  be  in  its  perihelion,  or  nearest  the  sun;  and  when  at  the 
point  B,  in  its  aphelion,  or  at  its  greatest  distance  from  the  sun.  The  difference 
m  these  distances  is  evidently  equal  to  F  f.  that  is.  equal  to  twice  the  eccen- 
tricity of  its  orbit.  In  every  revolution,  a  planet  passes  through  its  perihelion 
and  aphelion.  The  eccentricity  of  the  earth's  oibit  is  about  one  and  a  half 
millions  of  miles:  hence  she  is  three  millions  of  miles  nearer  the  sun  in  hei 
perihelion  than  in  her  aphelion. 

Now,  as  the  sun  remains  fixed  in  the  lower  focus  of  the  earth's  orbit,  it  is 
easy  to  perceive  that  a  line,  passing  centrally  through  the  sun  at  right  angles 
with  the  longer  axis  of  the  orbit,  will  divide  it  into  two  unequal  segments. 
Precisely  thus  it  is  divided  by  the  equinoctial. 

That  portion  of  the  earth's  orbit  which  lies  above,  the  sun,  or 
north  of  the  equinoctial,  contains  about  184  degrees;  while  that 
portion  of  it  which  lies  below  the  sun,  or  south  of  the  equinoctial, 
contains  only  176  degrees.  This  fact  shows  why  the  sun  con- 
tinues about  eight  days  longer  on  the  north  side  of  the  equator 
in  summer,  than  it  does  on  the  south  side  in  winter. 

The  points  of  the  earth's  orbit  which  correspond  to  its  greatest  and 
least  distances  from  the  sun,  are  called — the  former,  the  apogee,  and  the 
latter,  the  perigee  ,•  two  Greek  words,  the  former  of  which  signifies  from 
tin',  earth,  and  the  latter,  about  the  earth.  These  points  are  also  desig- 
nated by  the  common  name  of  apsides. 

The  earth  being  in  its  perihelion  about  the  1st  of  January,  and 
in  its  aphelion  the  1st  of  July,  we  are  three  millions  of  miles 
nearer  the  sun  in  winter  than  in  midsummer.  The  reason  why 
we  have  not,  as  might  be  expected,  the  hottest  weather  when 
the  earth  is  nearest  the  sun,  is,  because  the  sun,  at  that  time, 
having  retreated  to  the  southern  tropic,  shines  so  obliquely  on 
the  northern  hemisphere,  that  its  rays  have  scarcely  half  the  ef- 
fect of  the  summer  sun ;  and,  continuing  but  a  short  time  above 
the  horizon,  less  heat  is  accumulated  by  day  than  is  dissipated 
by  night. 

As  the  earth  performs  its  annual  revolution  around  the  sun, 
the  position  of  its  axis  remains  invariably  the  same, — always 
pointing  to  the  north  pole  of  the  heavens,  and  always  maintain- 
ing the  same  inclination  to  its  orbit.  This  seems  to  be  provi- 
dentially ordered  for  the  benefit  of  mankind.  If  the"  axis  of  the 
earth  always  pointed  to  the  center  of  its  orbit,  all  external  ob- 
jects would  appear  to  whirl  about  our  heads  in  an  inexplicable 
maze.  Nothing  would  appear  permanent.  The  mariner  could 
no  longer  direct  his  course  by  the  stars,  and  every  index  in  na- 
ture would  mislead  us. 

The  following  is  a  summary  of  our  knowledge  of  the  earth, 
as  a  planet;  epoch,  1st  Jahuary,  1801 : 

Mean  distance  from  the  sun  (95,000,000  miles),  its  radius  unity,  23984 
Distance  at  perihelion,  mean  distance  unity,  -  -  0.09832 

Distance  at  aphelion,  mean  distance  unity,  -  1.0168 

Mean  sideral  revolution,  in  solar  days,     *  -  365.2563612 


THE  EARTH. 


Mean  tropical  revolution,  in  solar  days, 

Mean  anomalistic  revolution,  in  solar  days, 

Entire  revolution  of  the  sun's  perigee,  in  solar  days, 

Mean  longitude,  corrected  20"  for  aberration, 

Motion  in  perihelion,  in  a  mean  solar  day, 

Mean  motion,  in  a  mean  solar  day, 

Mean  motion  in  a  sidereal  day, 

Motion  in  aphelion,  in  a  mean  solar  day, 

Mean  longitude  of  perihelion,      '     -  - 

E.  motion  of  line  of  apsides,  per  annum, 

Ditto,     referred  to  the  e'cliptic,     - 
Complete  tropical  revolution  of  apsides  in  years, 
Obliquity  of  ecliptic,  -  <~*'-.. 

Annual  diminution t)f  ditto,       '••         ;  ^ J   •: 
Semi  axis  major  of  nutation,  &  »-«=<  » 

A  nnual  luni-solar  precession,      -  • '    I*  *        • 

General  precession  in  longitude,         -  >«•     j 

( 'omplete  revolution  of  equinoxes,  in  years, 
Lunar  nutation  in  longitude,  -  ^ .«••  ,., 

Solar  nutation  in  longitude,        -  .    -     .  ~  ( 

Eccentricity  of  orbit,  semi  axis  major  as  unity, 
Decrease  of  ditto  in  100  years, 
Diurnal  acceleration  of  sidereal  or  mean  solar  time, 
From  the  vernal  equinox  to  the  summer  solstice, 
From  the  summer  solstice  to  the  autumnal  equinox, 
From  the  autumnal  equinox  to  the  winter  solstice, 
From  the  winter  solstice  to  the  vernal  e"quinox, 
Mass,  sun  as  unity,  •    ' 

Volume,     -  -  '*:,.".        '•"" 

Density,  sun  as  unity,        *•  j- 

Density,  water  as  unity,  ... 

Mean  diameter  (equatorial,  7924,  polar,  7898),  in  miles, 
Centrifugal  force  at  the  equator, 
Time  of  passage  of  light  from  the  sun,       -  ^ 

Motion  of  earth,  in  orbit,  in  the  same  time.          -     . 


01 
f>9 

58 
57 
30 

1 


-   365.2422414 
365.2595981 
7.645,793 
1000  39'  10". 2 
09  .9 
08  .33 
58  .64 
11  .5 
05  .0 
11  .8 
01  .9 

20,984 
23°  27'  56".  5 

0  .457 
9  .4 

50  .4 
50  .1 

25868 
17".  579 

1  .137 
0.016783568 

0.00004163 
3'  55".91 

92  d.  21  h.  50  m. 

93  13   44 
89   16   44 
89   01   33 

0.0000028173 
1.0 

3.9326 
5.6747 
7916 


0.00346 
8m.  13s.  .3 
*  20".25 


THE  MOON.  i 

THERK  is  no  object  within  the  scope  of  astronomical  observa- 
tion which  affords  greater  variety  of  interesting  investigation 
than  the  various  phases  and  motions  of  the  moon.  From  them, 
the  astronomer  ascertains  the  form  of  the  earth,  the  vicissitudes 
of  the  tides,  the  causes  of  eclipses  and  occultations,  the  distance 
of  the  sun,  and,  consequently,  the  magnitude  of  the  solar  system. 
These  phenomena,  which  are  perfectly  obvious  to  the  unassisted 


248  GEOGRAPHY  OF  THE  HEAVENS. 

eye,  served  as  a  standard  of  measurement  to  all  nations,  until 
the  advancement  of  science  taught  them  the  advantages  of  solar 
time.  It  is  to  these  phenomena  that  the  navigator  is  indebted 
for  that  precision  of  knowledge  which  guides  him  with  well- 
grounded  confidence  through  the  pathless  ocean. 

The  Hebrews,  the  Greeks,  the  Romans,  and,  in  general,  all 
the  ancients,  used  to  assemble  at  the  time  of  new  or  full  moon, 
to  discharge  the  duties  of  piety  and  gratitude,  for  her  unwearied 
attendance  on  the  earth,  and  all  her  manifold  uses.  • 

When  the  moon,  after  having  been  in  conjunction  with  the 
sun,  emerges  from  his  rays,  she  first  appears  in  the  evening,  a 
little  after  sunset,  like  a  fine  luminous  crescent,  with  its  convex 
side  toward  the  sun.  If  we  observe  her  the  next  evening,  we 
find  her  about  13°  further  east  of  the  sun  than  on  the  preceding 
evening,  and  her  crescent  of  light  sensibly  augmented.  Repeat- 
ing these  observations,  we  perceive  that  she  departs  further  and 
further  from  the  sun,  as  her  enlightened  surface  comes  more  and 
more  into  view,  until  she  arrives  at  her  first  quarter,  and  comes 
to  the  meridian  at.  sunset.  She  has  then  finished  her  course 
from  the  new  to  the  full,, ^g  half  her  enlightened  hemisphere  is 
turned  toward  the  earth. 

After  her  first  quarter,  she -appears  more  and  more  gibbous, 
as  she  recedes  further  and  further  from  the  sun,  until  she  has 
completed  just  half  her  revolution  around  the  earth,  and  is  seen 
risiag  in  the  east  when  the  sun  is  setting  in  the  west.  She 
then 'presents  her  enlightened  orb  full  to  our  view,  and  is  said 
t^  '  in  opposition;  because  she  is  then  on  the  opposite  side  of 
the  earth  with  respect  to  the  sun. 

In  the  first  half  of  her  orbit,  she  appears  to  pass  over  our 
heads  through  the  upper  hemisphere;  she  now  descends  below 
the  eastern  horizon,  to  pass  through  that  part  of  her  orbit  which 
lies  in  the  lower  hemisphere. 

After  her  full,  she  wanes  through  the  same  changes  of  appear- 
ance as  before,  but  in  an  inverted  order ;  and  we  see  her  in  the 
morning  like  a  fine  thread  of  light,  a  little  west  of  the  rising 
sun.  For  the  next  two  or  three  days,  she  is  lost  to  our  view, 
rising  and  setting  in  conjunction  with  the  sun;  after  which,  she 
passes  over,  by  reason  of  her  daily  motion,  to  the  east  side  of  the 
sun,  and  we  behold  her  again  a  new  moon,  as  before.  In 
changing  sides  with  the  sun,  she  changes  also  the  direction  of 
her  crescent.  Before  her  conjunction,  it  was  turned  to  the  east; 
it  is  now  turned  toward  the  west.  These  different  appearances 
of  the  moon  are  called  her  phases.  They  prove  that  she  shines 
not  by  any  light  of  her  own;  if  she  did,  being  globular,  we 
should  always  see  her  a  round,  full  orb,  like  the  sun. 

The  moon  is  a  satellite  to  the  earth,  about  which  she  revolves, 
in  an  elliptical  orbit,  in  29  days,  12  hours,  44  minutes,  and  3 


THE  MOON.  249 

seconds:  the  time  which  elapses  between  one  new  moon  and 
another.  This  is  called  her  synodic  revolution.  Her  revolution 
from  any  fixed  star  to  the  same  star  again  is  called  her  periodic 
or  .sidereal  revolution.  It  is  accomplished  in  27  days,  7  hours, 
43  minutes,  and  ll£  seconds;  but,  in  this  time,  the  earth  has 
advanced  nearly  as  many  degrees  in  her  orbit,  consequently,  the 
moon,  at  the  end  of  one  complete  revolution,  must  go  as  many 
degrees  further,  before  she  will  come  again  into  the  same  posi- 
tion with  respect  to  the  sun  and  the  earth. 

The  moon  is  the  nearest  of  all  the  heavenly  bodies,  being  30 
times  the  diameter  of  the  earth,  or  240,000  miles,  distant  from 
us.  Her  mean  daily  motion,  in  her  orbit,  is  nearly  14  times  as 
great  as  the  earth's;  since  she  not  only  accompanies  the  earth 
around  the  sun  every  year,  but,  in  the  meantime,  performs  nearly 
13  revolutions  about  the  earth. 

Although  the  apparent  motion  of  the  moon,  in  her  orbit,  is  greater 
than  that  of  any  other  heavenly  body,  since  she  passes  over,  at  a  mean 
rate,  no  less  than  13°  10'  35"  in  a  day ;  yet  this  is  to  be  understood  as 
angular  motion — motion  in  a  small  orbit,  and,  therefore,  embracing  a 
great  number  of  degrees,  and  but  comparatively  few  miles. 

The  moon,  though  apparently  as  K  as  the  sun,  is  the 
smallest  of  all  the  heavenly  bodies  that  are  visible  to  the  naked 
eye.  Her  diameter  is  but  2162  miles  ;  consequently,  her  surface 
is  13  times  less  than  that  of  the  earth,  and  her  bulk  49  times 
less.  It  would  require  70,000,000  of  such  bodies  to  equal  the 
volume  of  the  sun.  The  reason  why  she  appears  as  large  as 
the  sun,  when,  in  truth,  she  is  so  much  less,  is  because  she  is 
400  times  nearer  to  us  than  the  sun.  •'"* 

The  moon  revolves  once  on  her  axis,  exactly  in  the  time  that 
she  performs  her  revolution  around  the  earth.  This  is  evident 
from  her  always  presenting  the  same  side  to  the  earth;  for  if 
she  had  no  rotation  upon  an  axis,  every  part  of  her  surface  would 
be  presented  to  a  spectator  on  the  earth,  in  the  course  of  her 
synodical  revolution.  It  follows,  then,  that  there  is  but  one  day 
and  night  in  her  year,  containing,  both  together,  29  days,  12 
hours,  44  minutes,  and  3  seconds. 

As  the  moon,  while  revolving  about  the  earth,  is  carried  with 
it  at  the  same  time  around  the  sun,  her  path  is  extremely  irregu- 
lar, and  very  different  from  what  it  seems  to  be.  Like  a  point 
in  the  wheel  of  a  carriage,  moving  over  a  convex  road,  the  moon 
will  describe  a  succession  of  epicycloidal  curves,  which  are  al- 
ways concave  toward  the  sun,  not  very  Unlike  their  presentation 
in  the  following  figure. 


250  GEOGRAPHY   OF    THE   HEAVENS. 

THK    MOON'S    MOTION. 


Let  A  d  b  B  represent  a  portion  of  the  earth's  orbit ;  and  a  b  c  d  e  the  lunar 
orbit.  When  the.  earth  is  at  b.  the  new  moon  is  at  a;  and  while  the  earth  :s 
moving  from  b.  to  its  position  as  represented  in  the  figure,  the  moon  has  moved 
through  half  her  orbit,  from  a  to  c,  where  she  is  full;  so,  while  the  earth  is 
moving  from  its  present  position  to  d,  the  moon  describes  the  other  half  of  her 
orbit,  from  c  to  e,  where  she  is  again  in  conjunction. 

As  the  moon  turns  on  her  axis  only  as  she  moves  around  the 
earth,  it  is  plain  that  the  inhabitants  of  one  half  of  the  lunar 
world  are  totally  deprived  of  the  sight  of  the  earth,  unless  they 
travel  to  the  opposite  hemisphere.  This  we  may  presume  they 
will  do,  were  it  only  to  view  so  sublime  a  spectacle ;  for  it  is 
certain  that,  from  the  moon,  the  earth  appears  ten  times  larger 
than  any  other  body  in  the  universe. 

As  the  moon  enlightens  the  earth,  by  reflecting  the  light  of 
the  sun,  so  likewise  the  earth  illuminates  the  moon,  exhibiting 
to  her  the  same  phases  that  she  does  to  us,  only  in  a  contrary 
order.  And,  as  the  surface  of  the  earth  is  13  times  as  large  as 
the  surface  of  the  moon,  the  earth,  when  full  to  the  moon,  will 
appear  13  times  as  large  as  the  full  moon  to  us.  That  side  of 
the  moon,  therefore,  which  is  toward  the  earth,  may  be  said  to 
have  no  darkness  at  all,  the  earth  constantly  shining  upon  it 
with  extraordinary  splendor  when  the  sun  is  absent;  it  therefore 
enjoys  successively  two  weeks  of  illumination  from  the  sun, 
and  two  weeks  of  earth-light  from  the  earth.  The  other  side 
of  the  moon  has  alternately  a  fortnight's  light,  and  a  fortnight's 
darkness. 

As  the  earth  revolves  on  its  axis,  the  several  continents,  seas, 


THE  MOON.  251 

and  islands,  appear  to  the  lunar  inhabitants  like  so  many  spots, 
of  different  forms  and  brightness,  alternately  moving  over  its 
surface,  being  more  or  less  brilliant,  as  they  are  seen  through 
intervening  clouds.  By  these  spots,  the  lunarians  can  not  only 
determine  the  period  of  the  earth's  rotation,  just  as  we  do  that 
of  the  sun,  but  they  may  also  find  the  longitude  of  their  places, 
as  we  find  the  latitude  of  ours. 

As  the  full  moon  always  happens  when  the  moon  is  directly 
opposite  the  sun,  all  the  full  moons  in  our  winter,  must  happen 
when  the  moon  is  on  the  north  side  of  the  equinoctial,  because 
then  the  sun  is  on  the  south  side  of  it;  consequently,  at  the 
north  pole  of  the  earth,  there  will  be  a  fortnight's  moon-light 
and  .a  fortnight's  darkness  by  turns,  for  a  period  of  six  months, 
and  the  same  will  be  the  fact  during  the  sun's  absence  the  other 
six  months,  at  the  south  pole. 

The  moon's  axis  being  inclined  only  about  1£°  to  her  orbit, 
she  can  have  no  sensible  diversity  of  seasons;  from  which  we 
may  infer,  that  her  atmosphere  is  mild  and  uniform.  The  quanti- 
ty of  light  which  we  derive  from  the  moon  when  full,  is  at  least 
three  hundred  thousand  times  less  than  that  of  the  sun.* 

When  viewed  through  a  good  telescope,  the  moon  presents  a 
most  wonderful  and  interesting  aspect.  Besides  the  large  dark 
spots,  which  are  visible  to  the  naked  eye,  we  perceive  extensive 
valleys,  shelving  rocks,  and  long  ridges  of  elevated  mountains, 
projecting  their  shadows  on  the  plains  below.  Single  moun- 
tains occasionally  rise  to  a  great  hight,  while  circular  hollows, 
more  than  three  miles  deep,  seem  excavated  in  the  plains. 

Her  mountain  scenery  bears  a  striking  resemblance  to  the 
towering  sublimity  and  terrific  ruggedness  of  the  Alpine  regions, 
or  of  the  Appenines,  after  which  some  of  her  mountains  have 
been  named,  and  of  the  Cordilleras  of  our  own  continent. — 
Huge  masses  of  rock  rising  precipitously  from  the  plains,  lift 
their  peaked  summits  to  an  immense  hight  in  the  air,  while 
shapeless  crags  hang  over  their  projecting  sides,  and  seem  on 
the  eve  of  being  precipitated  into  the  tremendous  chasm  below. 

Around  the  base  of  these  frightful  eminences,  are  strewed 
numerous  loose  and  unconnected  fragments,  which  time  seems 
to  have  detached  from  their  parent  mass ;  and  when  we  examine 
the  rents  and  ravines  which  accompany  the  overhanging  cliffs, 
the  beholder  expects  every  moment  that  they  are  to  be  torn  from 
their  base,  and  that  the  process  of  destructive  separation  which 
he  had  only  contemplated  in  its  effects,  is  about  to  be  exhibited 
before  him  in  all  its  reality. 

*This  is  Mons.  Bouquer's  inference,  from  his  experiments,  as  stated  by  La 
Place,  in  his  work,  p,  43.  The  result  of  Dr.  Wollaston's  computations  wat 
different.  Professor  Leslie  makes  the  liffht  of  the  moon  150.000  times  less  thai 
that  of  the  sun :  it  was  formerly  reckoned  100,000  times  less. 


252  GEOGRAPHY  OF  THE  HEAVENS. 

The  range  of  mountains  called  the  Appenines,  which  traverses 
a  portion  of  the  moon's  disk  from  north-east  to  south-west,  and 
of  which  some  parts  are  visible  to  the  naked  eye,  rise  with  a 
precipitous  and  craggy  front  from  the  level  of  the  Mare  Imbrium^ 
or  Sea  of  showers.*  In  this  extensive  range  are  several  ridges 
whose  summits  have  a  perpendicular  elevation  of  four  miles, 
and  more;  and  though  they  often  descend  to  a  much  lower  level, 
they  present  an  inaccessible  barrier  on  the  north-east,  while  on 
the  south-west  they  sink  in  gentle  declivity  to  the  plains. 

There  is  one  remarkable  feature  in  the  moon's  surface,  which 
bears  no  analogy  to  any  thing  observable  on  the  earth.  This 
is  the  circular  cavities  which  appear  in  every  part  of  her  disk. 
Some  of  these  immense  caverns  are  nearly  four  miles  deep,  and 
forty  miles  in  diameter.  They  are  most  numerous  in  the  south- 
western part.  As  they  reflect  the  sun's  rays  more  copiously, 
they  render  this  part  of  her  surface  more  brilliant  than  any  other. 
They  present  to  us  nearly  the  same  appearance  as  our  earth 
might  be  supposed  to  present  to  the  moon,  if  all  our  great  lakes 
and  seas  were  dried  up. 

The  number  of  remarkable  spots  on  the  moon,  whose  latitude 
and  longitude  have  been  accurately  determined,  exceeds  two 
hundred.  The  number  of  seas  and  lakes,  as  they  were  formerly 
considered,  whose  length  and  breadth  are  known,  is  between 
twenty  and  thirty ;  while  the  number  of  peaks  and  mountains, 
whose  perpendicular  elevation  varies  from  a  fourth  of  a  mile  to 
five  miles  in  hight,  and  whose  bases  are  from  one  to  seventy, 
miles  in  length,  is  not  less  than  one  hundred  and  fifty. f 

i  •*  -fx 

Graphic;!  1  views  of  these  natural  appearances,  accompanied  with  min-j 
ute  and  familiar  descriptions,  constitute  what  is  called  Selenography,  froraj 
two  Greek  words,  which  mean  the  same  thing  in  regard  to  the  moon,  as 
Geography  does  hi  regard  to  the  earth. 

An  idea  of  some  of  these  scenes  may  he  formed  by  conceiv- 
ing a  plain  of  about  a  hundred  miles  in  circumference,  encircle^ 
by  a  range  of  mountains,  of  various  forms,  three  miles  in  perH 
pendicular  hight,  and  having  a  mountain  near  the  center,  whosd 
top  reaches  a  mile  and  a  half  above  the  level  of  the  plainJ 
From  the  top  of  this  central  mountain, 'the  whole  plain,  with  allj 
its  scenery,  would  be  distinctly  visible,  and  the  view  would  b* 
bounded  only  by  a  lofty  amphitheater  of  mountains,  rearing 
their'  summits  to  the  sky. 

*  The  name  of  a  lunar  spot. 

t  Brewster's  Selenography.  The  best  maps  of  the  moon  hitherto  published* 
ate  those  by  Madler  and  Beer ;  but  the  most  curious  and  complete  represent*! 
lion  of  the  telescopic  and  natural  appearances  of  the  moon,  is  to  be  seen  otj 
RiiBsel's  Lunar  Globe.  See  also  Selenographia,  by  C.  Blunt. 


THE  MOON.  253 

The  bright  spots  of  the  moon  are  the  mountainous  regions ; 
while  the  dark  spots  are  the  plains,  or  more  level  parts  of  her 
surface.  There  may  be  rivers  or  small  lakes  on  this  planet ; 
but  it  is  generally  thought,  by  astronomers  of  the  present  day, 
that  there  are  no  seas  or  large  collections  of  water,  as  was  former- 
ly supposed.  Some  of  these  mountains  and  deep  valleys  are 
visible  to  the  naked  eye ;  and  many  more  are  visible  through  a 
telescope  of  but  moderate  powers. 

A  telescope  which  magnifies  only  a  hundred  times,  will  show 
a  spot  on  the  moon's  surface,  whose  diameter  is  twelve  hundred 
and  twenty-three  yards;  and  one  which  magnifies  a  thousand 
times,  will  enable  us  to  perceive  any  enlightened  object  on  her 
surface  whose  dimensions  are  only  a  hundred  and  twenty-two 
yards,  which  does  not  much  exceed  the  dimensions  of  some  of 
our  public  edifices,  as  for  instance,  the  Capitol  at  Washington, 
or  St.  Paul's  Cathedral.  Professor  Frauenhofer,  of  Munich, 
recently  announced  that  he  had  discovered  a  lunar  edifice,  re- 
sembling a  fortification,  together  with  several  lines  of  road.  The 
celebrated  astronomer  Schroeter,  conjectures  the  existence  of  a 
great  city  on  the  east  side  of  the  moon,  a  little  north  of  her 
equator,  an  extensive  canal  in  another  place,  and  fields  of  vege- 
tation in  another.  But  no  reliance  is  to  be  placed  on  these  con- 
jectures. 


SOLAR  AND  LUNAR  ECLIPSES. 

OF  all  the  phenomena  of  the  heavens,  there  are  none  which 
engage  the  attention  of  mankind  more  than  eclipses  of  the  sun 
and  moon;  and  to  those  who  are  unacquainted  with  astronomy, 
nothing  appears  more  wonderful  than  the  accuracy  with  which 
they  can  be  predicted.  In  the  early  ages  of  antiquity  they  were 
regarded  as  alarming  deviations  from  the  established  laws  of 
nature,  presaging  great  public  calamities,  and  other  tokens  of 
the  divine  displeasure. 

In  China,  the  prediction  and  observance  of  eclipses  are  made  a  mattei 
of  state  policy,  in  order  to  operate  on  the  fears  of  the  ignorant,  and  im 
pose  on  them  a  superstitious  regard  for  the  occult  wisdom  of  their  rulers 
In  Mexico,  the  natives  fast  and  afflict  themselves  during  eclipses,  undei 
an  apprehension  that  the  Great  Spirit  is  in  deep  sufferance.  Some  of  th« 
northern  tribes  of  Indians  have  imagined  that  the  moon  had  been  wound- 
ed in  a  quarrel ;  and  others,  that  she  was  about  to  be  swallowed  by  a 
huge  fish. 

It  was  by  availing  himself  of  these  superstitious  notions  that  Columbus, 
when  shipwrecked  on  the  island  of  Jamaica,  extricated  himself  and  crew 
from  a  most  embarrassing  condition.  Being  driven  to  great  distress  for 
want  of  provisions,  and  the  natives  refusing  him  any  assistance,  when  all 

X 


254  GEOGRAPHY  OF  THE  HEAVENS. 

hope  seemed  to  be  cut  off,  he  bethought  himself  of  their  superstition  in 
regard  to  eclipses.  Having  assembled  the  principal  men  of  the  island,  he 
remonstrated  against  their  inhumanity,  as  teing  offensive  to  the  Great 
Spirit,  and  told  them  that  a  great  plague  was  even  then  ready  to  fall  upon 
them,  and  as  a  token  of  it,  they  would  that  night  see  the  moon  hide  her 
face  in  anger,  and  put  on  a  dreadfully  dark  and  threatening  aspect.  This 
artifice  had  the  desired  effect ;  for  the  eclipse  had  no  sooner  begun  than 
the  frightened  barbarians  came  running  with  all  kinds  of  provisions,  and 
throwing  themselves  at  the  feet  of  Columbus,  implored  his  forgiveness. — 
Almagest,  vol.  I,  55  c.,  v.  2. 

An  eclipse'of  the  sun  takes  place,  when  the  dark  body  of  the 
moon  passing  directly  between  the  earth  and  the  sun,  intercepts 
his  light.  This  can  happen  only  at  the  instant  of  new  moon,  or 
when  the  moon  is  in  conjunction ;  for  it  is  only  then  that  she 
passes  between  us  and  the  sun. 

An  eclipse  of  the  moon  takes  place  when  the  dark  body  of  the 
earth,  coming  between  her  and  the  sun,  intercepts  his  light,  and 
throws  a  shadow  on  the  moon.  This  can  happen  only  at  the 
time  of  full  moon,  or  when  the  moon  is  in  opposition;  for  it  is 
only  then  that  the  earth  is  between  her  and  the  sun. 

As  every  planet  belonging  to  the  solar  system,  both  primary 
and  secondary,  derives  its  light  from  the  sun,  it  must  cast  a 
shadow  toward  that  part  of  the  heavens  which  is  opposite  to  the 
sun.  This  shadow  is  of  course  nothing  but  a  privation  of  light 
in  the  space  hid  from  the  sun  by  the  opake  body,  and  will 
be  proportioned  to  the  magnitude  of  the  sun  and  planet. 

If  the  sun  and  planet  were  both  of  the  same  magnitude,  the 
form  of  the  shadow  cast  by  the  planet,  would  be  that  of  a  cylin- 
der, and  of  the  same  diameter  as  the  sun  or  planet.  If  the 
planet  were  larger  than  the  sun,  the  shadow  would  continually 
diverge,  and  grow  larger  and  larger;  but  as  the  sun  is  much 
larger  than  any  of  the  planets,  the  shadows  which  they  cast 
must  converge  to  a  point  in  the  form  of  a  cone ;  the  length  of 
which  will  be  proportional  to  the  size  and  distance  of  the 
planet  from  the  sun. 

The  magnitude  of  the  sun  is  such,  that  the  shadow  cast  by  each  of  the 
primary  planets  always  converges  to  a  point  before  it  reaches  any  other 
planet ;  so  that  not  one  of  the  primary  planets  can  eclipse  another.  The 
shadow  of  any  planet  which  is  accompanied  by  satellites,  may,  on  certain 
occasions,  eclipse  its  satellites ;  but  it  is  not  long  enough  to  eclipse  any 
other  body.  The  shadow  of  a  satellite,  or  moon,  may  also,  on  certain 
occasions,  fall  on  the  primary,  and  eclipse  it. 

When  the  sun  is  at  his  greatest  distance  from  the  earth,  and 
the  moon  at  her  least  distance,  her  shadow  is  sufficiently  long  to 
reach  the  earth,  and  extend  19,000  miles  beyond.  When  the 
sun  is  at  his  least  distance  from  the  earth,  and  the  moon  at  her 


ECLIPSES. 


255 


greatest,  her  shadow  will  not  reach  the  earth's  surface  by  20,000 
miles.  So  that  when  the  sun  and  moon  are  at  thei^mean 
distances,  the  cone  of  the  moon's  shadow  will  terminate  a  little 
before  it  reaches  the  earth's  surface. 

In  the  former  case,  if  a  conjunction  take  place  when  the 
center  of  the  moon  comes  in  a  direct  line  between  the  centers  of 
the  sun  and  earth,  the  dark  shadow  of  the  moon  will  fall  cen- 
trally upon  the  earth,  and  cover  a  circular  area  of  175  miles  in 
diameter.  To  all  places  lying  within  this  dark  spot,  the  sun 
will  be  totally  eclipsed,  as  illustrated  by  the  figure. 

ECLIPSES    OF    THE    SUN. 


In  consequence  of  the  earth's  motion  during  the  eclipse,  this  circular 
area  becomes  a  continued  belt  over  the  earth's  surface ;  being,  at  the 
broadest,  175  miles  wide.  This  belt  is,  however,  rarely  so  broad,  and 
often  dwindles  to  a  mere  nominal  line,  without  total  darkness. 

In  March,  this  line  extends  itself  from  S.  W.  to  N.  E.,  and  in  Sep. 
tember?  from  N.  W.  to  S.  E.  In  June,  the  central  line  is  a  curve,  going 
first  to  the  N.  E.,  and  then  to  the  S.  E. ;  in  December,  on  the  contrary, 
first  to  the  S.  E.,  and  then  to  the  N.  E.  To  all  places  within  2000 
miles,  at  least,  of  the  central  line,  the  eclipse  will  be  visible ;  and  the 
nearer  the  place  of  observation  is  to  the  line,  the  larger  will  be  the  eclipse. 
In  winter,  if  the  central  trace  be  but  a  little  northward  of  the  equator, 
and  hi  summer,  if  it  be  25°  N.  latitude,  the  eclipse  will  be  visible  all  over 
the  northern  hemisphere.  As  a  general  rule,  though  liable  to  many  modi- 
fications, we  may  observe,  that  places  from  200  to  250  miles  from  the 
central  line,  will  be  1 1  digits  eclipsed ;  from  thence  to  500  miles,  10  digits; 
and  so  on,  diminishing  one  digit  in  about  250  miles. 

If,  in  either  of  the  other  cases,  a  conjunction  take  place  when 
the  moon's  center  is  directly  between  the  centers  of  the  sun  and 
earth,  as  before,  the  moon  will  then  be  too  distant  to  cover  the 
entire  face  of  the  sun,  and  there  will  be  seen,  all  around  her  dark 
body,  a  slender  n'ng  of  dazzling  light. 


256 


GEOGRAPHY  OF  THE  HEAVENS. 


This  may  be  illustrated  by  the  foregoing  figure.  Suppose  C  D  to  re- 
present a  part  of  the  earth's  orbit,  and  the  moon's  shadow  to  terminate 
at  the  vertex  V.  The  small  space  between  ef  will  represent  the  breadth 
of  the  luminous  ring  which  will  be  visible  all  around  the  dark  body  of  tlie 
moon. 

Such  was  the  eclipse  of  February  12,  1831,  which  passed  over  the 
southern  states  from  S.  W.  to  N.  E.  It  was  the  first  annular  eclipse 
ever  visible  in  the  United  States.  A  long  the  path  of  this  eclipse,  the  lumin- 
ous ring  remained  perfect  and  unbroken  for  the  space  of  two  minutes 

From  the  most  elaborate  calculations,  compared  with  a  long  series  of 
observations,  the  length  of  the  moon's  shadow  in  eclipses,  and  her  distance 
from  the  sun  at  the  same  time,  vary  within  the  limits  of  the  following 
table: 


Length  of  shadow, 
Dist.  of  moon. 

Length  of  shadow  in 
semidiameters. 

Length 
in  miles. 

Distance  in 
semidiameters. 

Distance 
in  miles. 

Least 
Mean 
Greatest 

57.760Y3956= 
58.728X3956= 
59.730X3956= 

228.499 
232.328 
236,292 

55.902X^956= 
60.238V3956= 
63.862X3956= 

221.148 
238.300 
252,638 

Thus  it  appears  that  the  length  of  the  cone  of  the  moon's  shadow,  in 
eclipses,  varies  from  228,499  to  236,292  miles  ;  being  7,793  miles  longer 
in  the  one  case,  than  in  the  other.  The  inequality  of  her  distances  from 
the  earth  is  much  greater;  they  vary  from  221,148  to  252,638  miles, 
making  a  difference  of  31,490  miles. 

Although  a  central  eclipse  of  the  sun  can  never  be  total  to 
any  spot  on  the  earth  more  than  175  miles  broad  ;  yet  the  space 
over  which  the  sun  will  be  more  or  less  partially  eclipsed,  is 
nearly  5000  miles  broad. 

The  section  of  the  moon's  shadow,  or  her  penumbra,  at  the  earth's  sur- 
face, hi  eclipses,  is  far  from  being  always  circular.  If  the  conjunction 
happen  when  the  center  of  the  moon  is  a  little  above  or  a  little  below  the 
line  joining  the  centers  of  the  earth  and  sun,  as  is  most  frequently  the 
case,  the  shadow  will  be  projected  obliquely  over  the  earth's  surface,  and 
thus  cover  a  much  larger  space. 

To  produce  a  partial  eclipse,  it  is  not  necessary  that  the  shadow  should 
reach  the  earth  ;  it  is  sufficient  that  the  apparent  distance  between  the 
sun  and  moon  be  not  greater  than  the  sum  of  their  semidiameters, 

If  the  moon  performed  her  revolution  in  the  same  path  in 
which  the  sun  appears  to  move  ;  in  other  words,  if  her  orbit  lay 
exactly  in  the  plane  of  the  earth's  orbit,  the  sun  would  be 
eclipsed  at  the  time  of  every  new  moon,  and  the  moon  at  the 
time  of  every  full.  But  one  half  of  the  moon's  orbit  lies  about 
5°  on  the  north  side  of  the  ecliptic,  and  the  other  half  as  far  on 
the  south  side  of  it  ;  and,  consequently,  the  moon's  orbit  only 
' 


crosses  the   earth's  orbit  in  two  opposite  points, 
moon's  nodes. 


called  the 


ECLIPSES.  257 

When  the  moon  is  in  one  of  these  points,  or  nearly  so,  at  the 
time  of  the  new  moon,  the  sun  will  be  eclipsed.  When  she  is 
in  one  of  them,  or  nearly  so,  at  the  time  of  full  moon,  the  moon 
will  be  eclipsed.  But  at  all  other  new  moons,  the  moon  either 
passes  above  or  below  the  sun,  as  seen  from  the  earth  ;  and,  at 
all  other  full  moons,  she  either  passes  above  or  below  the  earth's 
shadow  ;  and,  consequently,  there  can  be  no  eclipse. 

If  the  moon  be  exactly  in  one  of  her  nodes  at  the  time  of  her 
change,  the  sun  will  be  centrally  eclipsed.  If  she  be  1£°  from 
her  node  at  the  time  of  her  change,  the  sun  will  appear  at  the 
equator  to  be  about  11  digits  eclipsed.  If  she  be  3°  from  her 
node  at  the  time  of  her  change,  the  sun  will  be  10  digits  eclipsed, 
and  so  on;  a  digit  being  the  twelfth  part  of  the  sun's  diameter. 
But  when  the  moon  is  about  18°  from  her  node,  she  will  just 
touch  the  outer  edge  of  the  sun,  at  the  time  of  her  change, 
without  producing  any  eclipse.  These  are  called  the  ecliptic 
limits.  Between  these  limits,  an  eclipse  is  doubtful,  and  re- 
quires a  more  exact  calculation. 


The  mean  ecliptic  limit  for  the  sun  is  16£°  on  each  side  of  the  node; 
the  mean  ecliptic  limit  for  the  moon  is  1  0£°  on  each  side  of  the  node. 
In  the  former  case,  then,  there  are  33°  about  each  node,  making,  in  all, 
66°  out  of  360°,  in  which  eclipses  of  the  sun  may  happen  :  in  the  latter 
case,  there  are  21°  about  each  node,  making,  in  all,  42°  out  of  360°,  in 
which  eclipses  of  the  moon  usually  occur.  The  proportion  of  the  solar 
to  the  lunar  eclipses,  therefore,  is  as  66  to  42,  or  as  11  to  7.  Yet  there 
are  more  visible  eclipses  of  the  moon,  at  any  given  place,  than  of  the 
sun  ;  because  a  lunar  eclipse  is  visible  to  a  whole  hemisphere,  a  solar 
eclipse  only  to  a  small  portion  of  it. 

The  greatest  possible  duration  of  the  annular  appearance  of  a 
solar  eclipse,  is  12  minutes  and  24  seconds  ;  and  the  greatest 
possible  time  during  which  the  sun  can  be  totally  eclipsed,  to 
any  part  of  the  world,  is  7  minutes  and  58  seconds.  The  moon 
may  continue  totally  eclipsed  for  one  hour  and  three  quarters. 

Eclipses  of  the  sun  always  begin  on  his  western  edge,  and 
end  on  his  eastern;  but  all  eclipses  of  the  moon  commence  on 
her  eastern  edge,  and  end  on  her  western. 

If  the  moon,  at  the  time  of  her  opposition,  be  exactly  in  her 
node,  she  will  pass  through  the  center  of  the  earth's  shadow, 
and  be  totally  eclipsed.  If,  at  the  time  of  her  opposition,  she 
be  within  6°  of  her  node,  she  will  still  pass  through  the  earth's 
shadow,  though  not  centrally,  and  be  totally  eclipsed  :  but  if 
she  be  12°  from  her  node,  she  will  only  just  touch  the  earth's 
shadow,  and  pass  it  without  being  eclipsed. 

The  duration  of  lunar  eclipses,  therefore,  depends  upon  the  difference 
between  the  diameter  of  the  moon  and  that  section  of  the  earth's  shadow 
x2 


258 


GEOGRAPHY  OF  THE  HEAVENS. 


through  which  she  passes.  When  an  eclipse  of  the  moon  is  both  total 
and  central,  its  duration  is  the  longest  possible,  amounting  nearly  to  4 
hours ;  but  the  duration  of  all  eclipses  not  central  varies  with  her  distance 
from  the  node. 


ECLIPSES    OF    THE    MOON. 


The  diameter  of  the  earth's  shadow,  at  the  distance  of  the 
moon,  is  nearly  three  times  as  large  as  the  diameter  of  the  moon  ; 
and  the  length  of  the  earth's  shadow  is  nearly  four  times  as  great 
as  the  distance  of  the  moon;  exceeding  it  in  the  same  ratio  that 
the  diameter  of  the  earth  does  the  diameter  of  the  moon,  which 
is  as  3.663  to  1. 

"  The  length  of  the  earth's  shadow,  and  its  diameter  at  the  distance  of  I  Diameter  of  the  [Length  of  'he 
(be  moon,  are  subject  to  the  variations  exhibited  in  the  following  table :  I          shadow.         |  shadow  in  n*. 


Sun  at  the  perigee 

Sun  at  his  mean  distance 

t 

Sun  at  the  apogee 

Moon  at  the  apogee 
Moon  at  her  mean  distanct 
Moon  at  the  perigee 
'  Moon  at  the  apogee 
[  Moon  at  her  m^an  distance 
Moon  at  the  perigee 
Moon  at  the  apogee 
|  Moon  at  her  mean  distance 
Moon  at  the  perigee 

5.2:  !2 
5.76-2 
6,292 
5.270 
5,799 
6.329 
5.306 
5:836 
6365 

842,217 
856.597 
|        871,262 

The  first  column  of  figures  expresses  the  diameter  of  the  earth's  sha- 
dow at  the  moon :  and  as  the  diameter  of  the  moon  is  only  2 1 62  miles, 
it  is  evident  that  it  can  always  be  comprehended  by  the  shadow,  which  is 
more  than  twice  as  broad  as  the  disk  of  the  moon. 

The  time  which  elapses  between  two  successive  changes  of 
the  moon,  is  called  a  Lunation,  which,  at  a  mean  rate,  is  about 
29£  days.  If  12  lunar  months  were  exactly  equal  to  the  12  so- 
lar months,  the  moon's  nodes  would  always  occupy  the  same 
points  in  the  ecliptic,  and  all  eclipses  would  happen  in  the  same 
months  of  the  year,  as  is  the  case  with  the  transits  of  Mercury 
and  Venus  :  but,  in  12  lunations,  or  lunar  months,  there  are  only 
354  days ;  and  in  this  time  the  moon  has  passed  through  both 
her  nodes,  but  has  not  quite  accomplished  her  revolution  around 
the  sun  :  the  consequence  is,  that  the  moon's  nodes  fall  back  in 
the  ecliptic  at  the  rate  of  about  19£°  annually ;  so  that  the 
eclipses  happen  sooner  every  year  by  about  19  days. 

As  the  moon  passes  from  one  of  her  nodes  to  the  other  in  173 
days,  there  is  just  this  period  between  two  successive  eclipses 


ECLIPSES.  259 

of  the  sun,  or  of  the  moon.  In  whatever  time  of  the  year,  then, 
we  have  eclipses  at  either  node,  we  may  be  sure  that  in  173 
days  afterwards,  we  shall  have  eclipses  at  the  other  node. 

As  the  moon's  nodes  fall  back,  or  retrograde  in  the  ecliptic,  at  the  rate 
of  19^°  every  year,  they  will  complete  a  backward  revolution  entirely 
around  the  ecliptic  to  the  same  point  again,  hi  18  years  225  days  {  in 
which  time  there  would  always  be  a  regular  period  of  eclipses,  if  any 
complete  number  of  lunations  were  finished  without  a  remainder.  But 
this  never  happens  ;  for  if  both  the  sun  and  moon  should  start  from  a 
line  of  conjunction  with  either  of  the  nodes  in  any  point  of  the  ecliptic, 
the  sun  would  perform  1 8  annual  revolutions  and  222°  of  another,  while 
the  moon  would  perform  230  lunations,  and  85°  of  another,  before  the 
node  would  come  around  to  the  same  point  of  the  ecliptic  again ;  so  that 
the  sun  would  then  be  138°  from  the  node,  and  the  moon  85°  from 
the  sun. 

But  after  223  lunations,  or  18  years  11  days,*  7  hours,  42  minutes, 
and  3 1  seconds,  the  sun,  moon,  and  earth,  will  return  so  nearly  in  the 
same  po-ition  with  respect  to  each  other,  that  there  will  be  a  regular 
return  of  the  same  eclipse*  for  many  ages.  This  grand  period  was 
discovered  by  the  Chaldeans,  and  by  them  called  Saros.  If,  therefore, 
to  the  mean  time  of  any  eclipse,  either  of  the  sun  or  moon,  we  add  the 
Chaldean  period  of  1 8  years  and  1 1  days,  we  shall  have  the  return  of 
the  same  eclipse.  This  mode  of  predicting  eclipses  will  hold  good  for  a 
thousand  years.  In  this  period  there  are  usually  70  eclipses;  41  of  the 
sun,  and  29  of  the  moon. 

The  number  of  eclipses  in  any  one  year,  cannot  be  less  than 
two,  nor  more  than  seven,  In  the  former  case,  they  will  both 
be  of  the  sun ;  and  in  the  latter,  there  will  be  five  of  the  sun, 
and  two  of  the  moon — those  of  the  moon  will  he  total.  There 
are  sometimes  six ;  but  the  usual  number  is  four:  two  of  the 
sun,  and  two  o£  the  moon. 

The  cause  of  this  variety  is  thus  accounted  for.  Although  the  sun 
usually  passes  by  both  nodes  only  once  in  a  year,  he  may  pass  the 
same  node  again  a  little  before  the  end  of  the  year.  In  consequence  of 
the  retrograde  motion  of  the  moon's  nodes,  be  will  come  to  either  of 
them  1 73  days  after  passing  the  other.  He  may,  therefore,  return  to 
the  same  node  in  about  34b  days,  having  thus  passed  one  node  twice 
and  the  other  once,  making  each  time,  at  each,  an  eclipse  of  both  the  sun 
and  the  moon,  or  six  in  all.  And,  since  12  lunations,  or  354  days  from 
the  first  eclipse  in  the  beginning  of  the  year,  leave  room  for  another 
new  moon  before  the  close  of  the  year,  and  since  this  new  moon  may 
fall  within  the  ecliptic  limit,  it  is  possible  for  the  sun  to  be  eclipsed  again. 
Thus  there  may  be  seven  eclipses  in  the  same  year. 

Again :  when  the  moon  changes  in  either  of  her  nodes,  she  cannot 
come  within  the  lunar  ecliptic  limit  at  the  next  full,  (though  if  she  be 

•If  there  are  four  leap  years  in  this  interval,  add  11  days ;  but  if  there  an> 
ftvt,  add  only  ten  days. 


260 


GEOGRAPHY  OF  THE  HEAVENS. 


full  in  one  of  her  nodes,  she  may  come  into  the  solar  ecliptic  limit  at 
her  next  change,  and  six  months  afterwards,  she  will  change  near  the 
other  node  ;  thus  making  only  two  eclipses. 

The  following  is  a  list  of  all  the  solar  eclipses  that  will  be  visible  in 
Europe  and  America  during  the  remainder  of  the  present  century. 


Year. 

Month. 

Day  and  hour. 

Digits 

Year. 

Month. 

Day  and  hour. 

Digits. 

1848 

Mar. 

5    7  50  A.  M- 

6^ 

1876 

Mar. 

25    4  11  P.  M. 

37 

1851 

July 

28    7  48  A.  M 

*\ 

1878 

July 

29    4  56  P.  M. 

7* 

1854 

May 

26    4  26  P.  M. 

u* 

1879 

July 

19    2    0  A.  M. 

1858 

Mar. 

15    6  14  A.  M. 

U 

1880 

Dec. 

U     7  30  A.  M. 

5i 

1859 
1860 

July 
July 

29    5  32  P.  M. 
18    7  23  A.  M 

i 

1-82 

1885 

May- 
Mar 

17    1    0  A.  M. 
16    0  35  A.  M. 

6* 

1S61 

Dec. 

31    7  30  A.  M 

3 

1886 

Aug. 

29    6  30  A.  M. 

0* 

1863 

May 

17    1    OP.  M. 

1887 

Aug. 

Iti  10    0  P.  M. 

1865 

Oct. 

19    9  10  A.  M. 

3| 

1890 

June 

17    3    0  A.  M. 

1866 

Oct. 

&  11  12  A.  M. 

0 

1891 

June 

600  Mer. 

1867 

Mar. 

6    3    0AM. 

ises 

Oct. 

20    0  19  P.  M. 

85 

1868 

Feb. 

23  10    0  A  M. 

1895 

Mar. 

26    4    0  A.  M. 

1869 

Aug. 

7    5  21  A.  M. 

10i 

1806 

Aug. 

900  Mer. 

1870 

Del. 

22    6    0  A.  M. 

1897 

July 

29    9    8  A.  M. 

4* 

1873 

May 

26    3    0  A.  M. 

1899 

June    |  8    0    0  Mer. 

1874  !     Oct". 

10    4    0  A.  M 

1900 

May 

28    8    9  A.  M 

11 

1875       Sept. 

29    5  56  A.  M 

IH 

The  eclipses  of  1854,  1869,  1875,  and  1900,  will  be  very  large.  In 
those  of  1858,  1861,  1873,  1875,  and  1880,  the  sun  will  me  eclipsed. 

Those  of  1854  and  1875,  will  be  annular.  The  scholar  can  con- 
tinue this  table,  or  extend  it  backward,  by  adding  or  subtracting  the 
Chaldean  period  of  18  years,  11  days,  7  hours,  54  minutes  and  31 
seconds . 

The  lunar  elements  for  the  1st  of  Jan.  1801,  are  as  follows: 


Mean  distance  (237,000  miles)  earth  eq.  diam, 

Mean  sidereal  revolution,  solar  days, 

Mean  tropical         «  «         " 

Mean  synodical     «  «         « 

Mean  longitude,  ... 

Mean  motion  in  a  mean  solar  day, 

Mean  long,  of  perigee, 

Mean  motion  of  apsides,  in  a  solar  day, 

Sidereal  rev.  of  apsides,  in  mean  solar  days, 

Tropical  revolution  of  ditto, 

Mean  anomaly,  ... 

Motion  of  ditto,  in  a  mean  solar  day, 

Mean  anomalistic  revolution,  in  solar  days 

Inclination  of  orbit,  ... 

Ascending  node,  ... 

Motion  of  ditto,  in  a  mean  solar  day, 

Sidereal  revolution  of  nodes, 

Synodical  revolution  of  ditto, 

Revolution  from  node  to  node, 

Eccentricity  of  orbit,         ... 

Greatest  equation  of  center, 


as  unity,         29.982175 

27  d.  7h.  43m.  11.5  s, 

27      7       43        04.7 

29     12       44        02.87 

118017'08".3 

13    10  35  .0 

-   2660  10'  7".5 

6'  41".0 

3232.5753 

3231.4751 

2120  6'  59".9 

130.064992 

27  d.  13  h.  18m.  37.4s. 

50    8'  47".9 

13  53    17  .7 

3    10  .6 

6793.39108 

346.619851 

27  d.  5  h.  5  m.  36  s. 

0.0518442 

6°  17'  12".7 


ECLIPSES. 


261 


inclination  of  axis,  .... 

Maximum  evection,  -  *.  > 

Maximum  variation,  ... 

Maximum  annual  equation, 

Minimum  horizontal  parallax,         ... 

Mean  ditto,  -  -  >.          > 

Maximum  ditto,  - 

Maximum  app.  diara.,  • 

Mean  ditto,  -  -  -          '  * 

Minimum  ditto,  • 

Mean  diameter  (about  2160  miles)  earth's  as  unity, 

Volume,  earth  as  unity,  ... 


Density, 


10  30'  10".8 
1    20  29  .9 

•  35  42  .0 
11    12  .0 

•  53  48  .0 
57  00  .9 

1  01  24  .0 
33  31  .1 
31  07  .0 
29  21  .9 

•  Ji       3.665 

0.01252 
0.615 


MARS. 

MARS  is  the  first  of  the  exterior  planets,  its  orbit  lying  im- 
mediately without,  or  beyond,  that  of  the  earth,  while  those  of 
Mercury  and  Venus  are  within. 

Mars  appears  to  the  naked  eye,  of  a  fine  ruddy  complexion ; 
resembling,  in  color,  and  apparent  magnitude,  the  star  Antares, 
near  which  it  frequently  passes.  It  exhibits  its  greatest  bril- 
liancy about  the  time  that  it  rises  when  the  sun  sets,  and  sets 
when  the  sun  rises;  because  it  is  then  nearest  the  earth.  It  is 
least  brilliant  when  it  rises  and  sets  with  the  sun;  for  then  it  is 
five  times  farther  removed  from  us  than  in  the  former  case. 

Its  distance  from  the  earth  at  its  nearest  approach  is  about 
fifty  millions  of  miles.  Its  greatest  distance  from  us  is  about 
two  hundred  and  forty  millions  of  miles.  In  the  former  case,  it 
appears  nearly  twenty-five  times  larger  than  in  the  latter.  When 
it  rises  before  the  sun,  it  is  our  morning  star;  when  it  sets  after 
the  sun,  it  is  our  evening  star. 

The  distance  of  all  the  planets  from  the  earth,  whether  they  be  interkn 
or  exterior  planets,  varies  within  the  limits  of  the  diameters  of  their  orbits  , 
for  when  a  planet  is  in  that  point  of  its  orbit  which  is  nearest  the  earth, 
it  is  evidently  nearer  by  the  whole  diameter  of  its  orbit,  than  when  it  is  hi 
the  opposite  point,  on  the  other  side  of  its  orbit.  The  apparent  diameter 
of  the  planet  will  also  vary  for  the  same  reason,  and  to  the  same  degree. 

Mars  is  sometimes  seen  in  opposition  to  the  sun,  and  some- 
times in  superior  conjunction  with  him  ;  sometimes  gibbous,  but 
never  horned.  In  conjunction,  it  is  never  seen  to  pass  over  the 


262  GEOGRAPHY  OF  THE  HEAVENS. 

sun's  disk,  like  Mercury  and  Venus.  This  proves  not  only  that 
its  orbit  is  exterior  to  the  earth's  orbit,  but  that  it  is  an  opake 
body,  shining  only  by  the  reflection  of  the  sun. 

The  motion  of  Mars  through  the  constellations  of  the  zodiac 
is  but  little  more  than  half  as  great  as  that  of  the  earth  ;  it  being 
generally  about  fifty-seven  days  in  passing  over  one  sign,  which 
is  at  the  rate  of  a  little  more  than  half  a  degree  each  day.  Thus, 
if  we  know  what  constellation  Mars  enters  to  day,  we  may  con- 
clude that  two  months  hence  it  will  be  in  the  next  constellation  ; 
four  months  hence,  in  the  next ;  six  months,  in  the  next,  and  so 
on. 

Mars  performs  his  revolution  around  the  sun  in  one  year  and 
ten  and  a  half  months,  at  the  distance  of  a  hundred  and  forty- 
five  millions  of  miles ;  moving  in  its  orbit  at  the  mean  rate  of 
fifty-five  thousand  miles  an  hour.  Its  diurnal  rotation  on  its  axis 
is  performed  in  twenty-four  hours,  thirty-seven  minutes,  and 
twenty-one  and  a  third  seconds  ;  which  makes  its  day  about 
forty-four  minutes  longer  than  ours. 

Its  mean  sidereal  revolution  is  performed  in  686.9796458  solar  days; 
or  in  686  days,  23  hours,  30  minutes,  41.4  seconds.  Its  synodical  revo- 
lution is  performed  hi  779.936  solar  days ;  or  in  779  days,  22  hours,  27 
minutes,  and  60  seconds. 

Its  form  is  that  of  an  oblate  spheroid,  whose  polar  diameter 
is  to  its  equatorial,  as  fifteen  is  to  sixteen,  nearly.  Its  mean 
diameter  is  4222  miles.  Its  bulk,  therefore,  is  seven  times  less 
than  that  of  the  earth ;  and  being  fifty  millions  of  miles  farther 
from  the  sun,  it  receives  from  him  only  half  as  much  light  and 
heat. 

The  inclination  of  its  axis  to  the  plane  of  its  orbit,  is  about 
28$°.  Consequently,  its  seasons  must  be  very  similar  to  those 
of  the  earth.  Indeed,  the  analogy  between  Mars  and  the  earth 
is  greater  than  the  analogy  between  the  earth  and  any  other 
planet  of  the  solar  system.  Their  diurnal  motion,  and  of  course 
the  length  of  their  days  and  nights,  are  nearly  the  same ;  the 
obliquity  of  their  ecliptics,  on  which  the  seasons  depend,  are 
not  very  different ;  and,  of  all  the  superior  planets,  the  distance 
of  Mars  from  the  sun  is  by  far  the  nearest  to  that  of  the  earth ; 
nor  is  the  length  of  its  year  greatly  different  from  ours,  when 
compared  with  the  years  of  Jupiter,  Saturn,  and  Herschel. 

To  a  spectator  on  this  planet,  the  earth  will  appear  alternate- 
ly, as  a  morning  and  evening  star ;  and  will  exhibit  all  the 
phases  of  the  moon,  just  as  Mercury  and  Venus  do  to  us  ;  and 
sometimes,  like  them,  will  appear  to  pass  over  the  sun's  disk 
like  a  dark  round  spot.  Our  moon  will  never  appear  more  than 
a  quarter  of  a  degree  from  the  earth,  although  her  distance  from 


MARS.  263 

it  is  240,000  miles.     If  Mars  be  attended  by  a  satellite,  it  is  too 
small  to  be  seen  by  the  most  powerful  telescopes. 

When  it  is  considered  that  Vesta,  the  smallest  of  the  asteroids,  which 
is  once  at  id  a  half  times  the  distance  of  Mars  from  us,  and  only  269 
miles  in  diameter,  is  perceivable  in  the  open  space,  and  that  without  the 
presence  of  a  more  conspicuous  body  to  point  it  out,  we  may  reasonably 
conclude  that  Mars  is  without  a  moon. 

The  progress  of  Mars  in  the  heavens,  and  indeed  of  all  the  superior 
planets,  will,  like  Mercury  and  Venus,  sometimes  appear  direct,  some- 
times retrograde,  and  sometimes  he  will  seem  stationary.  When  a  su- 
perior planet  first  becomes  visible  in  the  morning,  west  of  the  sun,  a  little 
after  its  conjunction,  its  motion  is  direct,  and  also  most  rapid.  When  it 
is  first  seen  east  of  the  sun,  in  the  evening,  soon  after  its  opposition,  its 
motion  is  retrograde.  These  retrograde  movements  and  stations,  as  they 
appear  to  a  spectator  from  the  earth,  are  common  to  all  the  planets,  and 
demonstrate  the  truth  of  the  Copernican  system. 

The  telescopic  phenomena  of  Mars  afford  peculiar  interest  to 
astronomers.  They  behold  its  disk  diversified  with  numerous 
irregular  and  variable  spots,  and  ornamented  with  zones  and 
belts  of  varying  brilliancy,  that  form,  and  disappear,  by  turns. 
Zones  of  intense  brightness  are  to  be  seen  in  its  polar  regions, 
subject,  however,  to  gradual  changes.  That  of  the  southern 
pole  is  much  the  most  brilliant.  Dr.  Herschel  supposes  that 
they  are  produced  by  the  reflection  of  the  sun's  light  from  the 
frozen  regions,  and  that  the  melting  of  these  masses  of  polar  ice 
is  the  cause  of  the  variation  in  their  magnitude  and  appearance. 

He  was  the  more  confirmed  in  these  opinions  by  observing, 
that  after  the  exposure  of  the  luminous  zone  about  the  north 
pole  to  a  summer  of  eight  months,  it  was  considerably  decreased, 
while  that  on  the  south  pole,  which  had  been  in  total  darkness 
during  eight  months,  had  considerably  increased. 

He  observed,  further,  that  when  this  spot  was  most  luminous, 
the  disk  of  Mars  did  not  appear  exactly  round,  and  that  the 
bright  part  of  its  southern  limb  seemed  to  be  swollen  or  arched 
out  beyond  the  proper  curve. 

The  extraordinary  hight  and  density  of  the  atmosphere  of 
Mars,  are  supposed  to  be  the  cause  of  the  remarkable  redness  of 
its  light. 

It  has  been  found  by  experiment,  that  when  a  beam  of  white 
light  passes  through  any  colorless  transparent  medium,  its 
color  inclines  to  red,  in  proportion  to  the  density  of  the  medium, 
and  the  space  through  which  it  has  traveled.  Thus  the  sun, 
moon,  and  stars,  appear  of  a  reddish  color  when  near  the  hori- 
zon ;  and  every  luminous  object,  seen  through  a  mist,  is  of  a 
ruddy  hue. 


264  GEOGRAPHY  OF  THE  HEAVENS. 

This  phenomenon  may  be  thus  explained: — The  momentum  of  the 
red,  or  least  refrangible  rays,  being  greater  than  that  of  the  violet,  or  most 
refrangible  rays,  the  former  will  make  their  way  through  the  resisting 
medium,  while  the  latter  are  either  reflected  or  absorbed.  The  color  of 
the  beam,  therefore,  when  it  reaches  the  eye,  must  partake  of  the  color 
of  the  least  refrangible  rays,  and  this  color  must  increase  with  the  dis- 
tance. The  dim  light,  therefore,  by  which  Mars  is  illuminated,  having 
to  pass  twice  through  its  atmosphere  before  it  reaches  the  earth,  must  be 

r'ved  of  a  great  proportion  of  its  violet  rays,  and  consequently  then  be 
Dr.  Brewster  supposes  that  the  difference  of  color  among  the  other 
planets,  and  even  the  fixed  stars,  is  owing  to  the  different  bights  and 
densities  of  their  atmospheres. 

The  elliptical  elements  of  Mars,  for  Jan.  1st,  1801,  are  as  follows: 

Mean  distance  (142,000,000  miles),  earth's  as  unity,  .  .  1.5236923 

Mean  sid.  rev., 686  d.  23  h.  30m.  41.4s. 

Mean  syn.  do.,  in  solar  days, 779.936 

Long,  of  perihelion 332°  23'  56".« 

Motion  of  apsides,  E.  per.  an., 15".8 

"  apparent  for  precession, 1'  05".y 

Inclination  of  orbit, 1°  51'  06".2 

Annual  decrease  of  do., 0".014 

Long,  of  Asc.  node, 48°  0' 03". 5 

Motion  of  do.  W.  per  annum, 23".3 

«  «  «  E.  referred  to  the  ecliptic, 26".8 

Eccentricity  of  orbit.  Semi  maj.  axis  unity, 0.0933070 

Secular  increase  of  do., 0.00090176 

Greater  equaiion  of  center, 10°  40'  50" 

Annual  derrease  of  do.,  ..'...' 0".37 

Rotation  on  axis 24  h.  37  m.  20.6  s, 

Inclination  of  axis 30°  18'  10".8 

Mean  app.  diam., 6".29 

Diam.  at  conjunction, 3".60 

«  "  opposition, .  18.28 

True  diam.  (4 100  miles),  earth  as  unity, 0.517 

Volume,  earth  as  unity,  .  .• 0.1386 

3,  sun  as  unity, 0.0000003927 


THE  ASTEROIDS,  OR  TELESCOPIC  PLANETS. 

ASCENDING  higher  in  the  solar  system,  we  find,  between  the 
orbits  of  Mars  and  Jupiter,  a  cluster  of  nine  small  planets,  which 
present  a  variety  of  anomalies  that  distinguish  them  from  all  the 
older  planets  of  the  system.  They  were  all  discovered  within 
the  present  century. 


THE  ASTEROIDS.  265 

The  dates  of  their  discovery,  and  the  names  of  their  discoverers,  are  as 
follows  : 

Ceres,  January  1,  1801,  by  M.  Piazzi,  of  Palermo. 
Pallas,  March  28,  1802,  by  M.  Gibers,  of  Bremen. 
Juno,  September  1,  1804,  by  M.  Harding,  of  Bremen. 
Vesta,  March  29,  1807,  by  M.  Olbers,  of  Bremen. 
Astrea,  8th  December,  1845,  by  Hencke,  of  Dreisen. 
Hebe,  5th  July,  1847,  «         «       «       '< 

Iris,  13th  August,  1847,  by  Hind,  of  London. 
Flora,  18th  Oct.,  1847,     "      «       "        " 
Metis,  25th  April,  1848,  by  Graham,  of  Sligo. 

The  scientific  Bode*  entertained  the  opinion,  that  the  plane- 
tary distances,  above  Mercury,  formed  a  geometrical  series,  each 
exterior  orbit  being  double  the  distance  of  its  next  interior  one, 
from  the  sun;  a  fact  which  obtains  with  remarkable  exactness 
between  Jupiter,  Saturn,  and  Herschel.  But  this  law  seemed 
to  be  interrupted  between  Mars  and  Jupiter.  Hence  he  inferred, 
that  there  was  a  planet  wanting  in  that  interval  ;  which  is  now 
happily  supplied  by  the  discovery  of  the  four  star-form  planets, 
occupying  the  very  space  where  the  unexplained  vacancy  pre- 
sented a  strong  objection  to  his  theory. 

These  bodies  are  much  smaller  in  size  than  the  older  planets  — 
they  all  revolve  at  nearly  the  same  distances  from  the  sun,  and 
perform  their  revolutions  in  nearly  the  same  periods,  —their  orbits 
are  much  more  eccentric,  and  have  a  much  greater  inclination  to 
the  ecliptic,  —  and  what  is  altogether  singular,  except  in  the  case 
of  comets  —  nearly  all  cross  each  other  ,•  so  that  there  is  even  a  pos- 
sibility that  two  of  these  bodies  may,  some  time,  in  the  cour&e 
of  their  revolutions,  come  into  collision. 

The  orbit  of  Vesta  is  so  eccentric,  that  she  is  sometimes  far- 
ther from  the  sun  than  either  Ceres,  Pallas,  or  Juno,  although 
her  mean  distance  is  many  millions  of  miles  less  than  theirs. 
The  orbit  of  Vesta  crosses  the  orbits  of  all  the  other  three,  in 
two  opposite  points. 

From  these  and  other  circumstances,  many  eminent  astrono- 
mers are  of  opinion,  that  these  four  planets  are  the  fragments  of 
a  large  celestial  body  which  once  revolved  between  Mars  and 
Jupiter,  and  which  burst  asunder  by  some  tremendous  convul- 

*  According  to  him,  the  distances  of  the  planets  may  be  expressed  nearly  a* 
follows:  the  earth's  distance,  from  the  sun  being  10. 

Asteroids  ...........  .-4-4-3X23  =28 

Jupiter,  ..............  4-I-3X21  =52 

Saturn,  ...............  44-3y26=100 

Herschel.  ............  4-i-3X2«  =196 


Mercury. 4  =4 

Venus, 4+3X  1  =7 

The  Earth, 4-{-3><  2=10 

Mars,   4+3X22=16 


Comparing  these  values  with  the  actual  mean  distances  of  the  planets  from 
the  sun.  we  cannot  but  remark  the  near  agreement,  and  can  scarcely  hesitate 
to  pronounce  that  the  respective  distances  of  the  planets  from  the  sun,  were 
assigned  according  to  a  law.  although  we  are  entirely  ignorant  of  the  exact 
law,  and  of  the  reason  for  that  law.  —  Brinklfy''s  Elements,  p.  89. 


266  GEOGRAPHY  OF  THE  HEAVENS. 

sion,  or  some  external  violence.  The  discovery  of  Ceres  by 
Piazzi,  on  the  first  day  of  the  present  century,  drew  the  atten- 
tion of  all  the  astronomers  of  the  age  to  that  region  of  the  sky, 
and  every  inch  of  it  was  minutely  explored.  The  consequence 
was,  that,  in  the  year  following,  Dr.  Olbers,  of  Bremen,  an- 
nounced to  the  world  the  discovery  of  Pallas,  situated  not  many 
degrees  from  Ceres,  and  very  much  resembling  it  in  size. 

From  this  discovery,  Dr.  Olbers  first  conceived  the  idea  that 
these  bodies  might  be  the  fragments  of  a  former  world  ;  and  if 
so,  that  other  portions  of  it  might  be  found  either  in  the  same 
neighborhood,  or  else,  having  diverged  from  the  same  point, 
"  they  ought  to  have  two  common  points  of  reunion,  or  two 
nodes  in  opposite  regions  of  the  heavens  through  which  all  the 
planetary  fragments  must  sooner  or  later  pass." 

One  of  these  nodes  he  found  to  be,  in  the  constellation  Virgo, 
and  the  opposite  one,  in  the  Whale ;  and  it  is  a  remarkable  co- 
incidence that  it  was  in  the  neighborhood  of  the  latter  constel- 
lation that  Mr.  Harding  discovered  the  planet  Juno.  In  order, 
therefore,  to  detect  the  remaining  fragments,  if  any  existed,  Dr. 
Olbers  examined,  three  times  every  year,  all  the  small  stars  in 
Virgo,  and  the  Whale ;  and  it  was  actually  in  the  constellation 
Virgo,  that  he  discovered  the  planet  Vesta.  Some  astronomers 
think  it  not  unlikely  that  other  fragments  of  a  similar  description 
may  hereafter  be  discovered.  Dr.  Brewster  attributes  the  fall 
of  meteoric  stones  to  the  smaller  fragments  of  these  bodies  hap- 
pening to  come  within  the  sphere  of  the  earth's  attraction. 

Meteoric  stones,  or  what  are  generally  termed  aerolites,  are  stones 
which  sometimes  fell  from  the  upper  regions  of  the  atmosphere,  upon  the 
earth.  The  substance  of  which  they  are  composed,  is,  for  the  most  part, 
metallic  ;  but  the  ore  of  which  it  consists  is  not  to  be  found  in  the  same 
constituent  proportions  in  any  known  substance  upon  the  earth.  Their 
fall  is  generally  preceded  by  a  luminous  appearance,  a  hissing  noise,  and 
a  loud  explosion  ;  and,  when  found  immediately  after  their  descent,  they 
are  always  hot,  and  usually  covered  with  a  black  crust,  indicating  a  state 
of  exterior  fusion. 

Their  size  varies  from  that  of  small  fragments  of  inconsiderable  weight, 
to  that  of  the  most  ponderous  masses.  They  have  been  found  to  weigh 
from  300  pounds  to  several  tons ;  and  they  have  descended  to  the  earth 
with  a  force  sufficient  to  bury  them  many  feet  under  the  surface. 

Some  have  supposed  that  they  are  projected  from  volcanoes  in  the 
moon  ;  others,  that  they  proceed  from  volcanoes  on  the  earth ;  while 
others  imagine  that  they  are  generated  in  the  regions  of  the  atmosphere  ; 
but  the  truth,  probably,  is  not  yet  ascertained.  In  some  instances,  these 
stones  have  penetrated  through  the  roofs  of  houses,  and  proved  destruc- 
tive to  the  inhabitants. 

If  we  carefully  compute  the  force  of  gravity  in  the  moon,  we  shall  find, 
that  if  a  body  were  projected  from  her  surface  with  a  momentum  that 


THE  ASTEROIDS/  267 

would  cause  it  to  move  at  the  rate  of  8,200  feet  in  the  first  second  of 
time,  and  in  the  direction  of  a  line  joining  the  centers  of  the  earth  and 
moon,  it  would  not  fall  again  to  the  surface  of  the  moon  ;  but  would  be- 
come a  satellite  to  the  earth.  Such  an  impulse  might,  indeed,  cause  it, 
even  after  many  revolutions,  to  fall  to  the  earth.  The  fall,  therefore,  of 
these  stones,  from  the  air,  may  be  accounted  for  in  this  manner. 

Mr.  Harte  calculates,  that  even  a  velocity  of  6000  feet  in  a  second, 
would  be  sufficient  to  carry  a  body  projected  from  the  surface  of  the 
moon  beyond  the  power  of  her  attraction.  If  so,  a  projectile  force  three 
times  greater  than  that  of  a  cannon,  would  carry  a  body  from  the  moon 
beyond  the  point  of  equal  attraction,  and  cause  it  to  reach  the  earth.  A 
force  equal  to  this  is  often  exerted  by  our  volcanoes,  and  by  subterranean 
steam.  Hence,  there  is  no  impossibility  in  the  supposition  of  their 
coming  from  the  moon ;  but  yet  I  think  the  theory  of  aerial  consolida- 
tion the  more  plausible. 

Of  the  old  asteroids  we  present  the  following  notices : 

Vesta  appears  like  a  star  of  the  5th  or  6th  magnitude,  shining 
with  a  pure  steady  radiance,  and  is  the  only  one  of  the  aster- 
oids which  can  be  discerned  by  the  naked  eye. 

JUNO,  the  next  planet  in  order  after  Vesta,  revolves  around 
the  sun  in  four  years,  four  and  a  half  months,  at  the  mean  dis- 
tance of  two  hundred  and  fifty-four  millions  of  miles,  moving 
in  her  orbit  at  the  rate  of  forty-one  thousand  miles  an  hour. 
Her  diameter  is  estimated  at  1393  miles.  This  would  make  her 
magnitude  a  hundred  and  eighty-three  times  less  than  the  earth's. 
The  light  and  heat  which  she  receives  from  the  sun  is  seven 
times  less  than  that  received  by  the  earth. 

The  eccentricity  of  her  orbit  is  so  great,  that  her  greatest  dis- 
tance from  the  sun  is  nearly  double  her  least  distance;  so  that, 
when  she  is  in  her  perihelion,  she  is  nearer  the  sun  by  a  hundred 
and  thirty  millions  of  miles,  than  when  she  is  in  her  aphelion. 
This  great  eccentricity  has  a  corresponding  effect  upon  her  rate 
of  motion ;  for  being  so  much  nearer,  and  therefore  so  much 
more  powerfully  attracted  by  the  sun  at  one  time  than  at  another, 
she  moves  through  that  half  of  her  orbit  which  is  nearest  the^ 
sun,  in  one  half  of  the  time  that  she  occupies  in  completing  the* 
other  half. 

According  to  Schroeter,  the  diameter  of  Juno  is  1425  miles ;  and  she 
is  surrounded  by  an  atmosphere  more  dense  than  that  of  any  of  the 
other  planets.  Schroeter  also  remarks,  that  the  variation  in  her  brilliancy 
is  chiefly  owing  to  certain  changes  in  the  density  of  her  atmosphere ;  at 
the  same  time  he  thinks  it  not  improbable  that  these  changes  may  arise 
from  a  diurnal  revolution  on  her  axis. 

CERES,  the  planet  next  in  order  after  Juno,  revolves  about  the 
sun  in  four  years,  seven  and  a  third  months,  at  the  mean  distance 
of  two  hundred  and  sixty-three  and  a  half  millions  of  miles, 


268        GEOGRAPHY  OF  THE  HEAVENS. 

moving  in  her  orbit  at  the  rate  of  forty-one  thousand  miles  an 
hour.  Her  diameter  is  estimated  at  1582  miles,  which  makes 
her  magnitude  a  hundred  and  twenty-five  times  less  than  the 
earth's.  The  intensity  of  the  light  and  heat  which  she  receives 
from  the  sun,  is  about  seven  and  a  half  times  less  than  that  of 
those  received  by  the  earth. 

Ceres  shines  with  a  ruddy  color,  and  appears  to  be  only  about 
the  size  of  a  star  of  the  eighth  magnitude.  Consequently  she  is 
never  seen  by  the  naked  eye.  She  is  surrounded  by  a  species 
of  cloudy  or  nebulous  light,  which  gives  her  somewhat  the  ap- 
pearance of  a  comet,  forming,  according  to  Schroeter,  an  atmo- 
sphere six  hundred  and  seventy-five  miles  in  hight. 

Ceres,  as  has  been  said,  was  the  first  discovered  of  the  asteroids.  At 
her  discovery,  astronomers  congratulated  themselves  upon  the  harmony 
of  the  system  being  restored.  They  had  long  wanted  a  planet  to  fill  up 
the  great  void  between  Mars  and  Jupiter,  in  order  to  make  the  system 
complete  in  their  own  eyes ;  but  the  successive  discoveries  of  Pallas  and 
Juno  again  introduced  confusion,  and  presented  a  difficulty  which  they 
were  unable  to  solve,  till  Dr.  Olbers  suggested  the  idea  that  these  small 
anomalous  bodies  were  merely  the  fragments  of  a  larger  planet,  which 
had  been  exploded  by  some  mighty  convulsion.  Among  th»>  most  able 
and  decided  advocates  of  this  hypothesis,  is  Dr.  Brewster,  of  Edinburgh. 

PALLAS,  the  next  planet  in  order  after  Ceres,  performs  her  re- 
volution around  the  sun  in  four  years,  seven  and  two-third  months, 
at  the  mean  distance  of  two  hundred  and  sixty-four  millions  of 
miles,  moving  in  her  orbit  at  the  rate  of  forty-one  thousand  miles 
an  hour.  Her  diameter  is  estimated  at  2025  miles,  which  is  but 
little  less  than  that  of  our  moon.  It  is  a  singular  and  very  re- 
markable phenomenon  in  the  solar  system,  that  two  planets, 
(Ceres  and  Pallas,)  nearly  of  the  same  size,  should  be  situated 
at  equal  distances  from  the  sun,  revolve  about  him  in  the  same 
period,  and  in  orbits  that  intersect  each  other.  The  difference 
in  the  respective  distances  of  Ceres  and  Pallas  is  less  than  a 
million  of  miles.  The  difference  in  their  sidereal  revolutions, 
according  to  some  astronomers,  is  but  a  single  day  ! 

The  calculation  of  the  latitude  and  longitude  of  the  astoroids,  is  a 
labor  of  extreme  difficulty,  requiring  more  than  four  hundred  equations 
to  reduce  their  anomalous  perturbations  to  the  true  place.  This  arises 
from  the  want  of  auxiliary  tables,  and  from  the  fact  that  the  elements 
of  the  star- form  planets,  are  very  imperfectly  determined.  Whether  any 
of  the  asteroids  has  a  rotation  on  its  axis,  remains  to  be  ascertained.  The 
following  table  exhibits  the  present  state  of  knowledge  with  reference  to 
the  asteroids.  The  longitudes  are  referred  to  the  mean  equinox,  Jan.  1, 
1848,  except  Metis,  which  is  for  April  30,  1848. 


THE  ASTEROIDS. 


269 


The  following  tables  present  a  synopsis  of  the  present  knowledge  of 
the  asteriods. 


Names. 

1  Flora, 

2  Vesta, 

3  Iris, 

4  Metis, 

5  Hebe, 

6  Astrea, 

7  Juno, 

8  Ceres, 

9  Pallas, 


Rev.  in  Sid.  days. 
1193.25 
1325.22 
1345.16 
1346.40 
1375.25 
1510.75  . 
1594.68 
1680.96 
1685.55 


Aph.  Dist. 
2.547126 
2.571997 
2.935335 

2.903557 
3.060943 
3.349363 
2.979793 
3.438312 


Peri.  Disu 
1.856244 
2.150345 
1.834262 

1.936886 
2.092456 
1.993166 
2.553746 
2.105304 


ELEMENTS. 


Names. 

Epoch. 

Mean  anomaly. 

Long.  asc.  node. 

1   Flora, 

1848  Jan.        1.0 

350  53'  32".  0 

110°18'50".8 

2  Vesta, 

1847  April,      4.0 

310    46  14  .7 

103    22  01  .3 

3  Iris, 

1847  Sept.       1.0 

298    16  37  .2 

259    45   19  .6 

4  Metis, 

1848  April,   30.0 

141    54  11  .82 

68    29  40  .4 

5  Hebe, 

1847  July,     10.0 

274    54  02  .6 

138    40  44  .8 

6  Astrea, 

1847  March,  16.0 

63    30  49  .3 

141    29  29  .2 

7  Juno, 

1847  July,       9.5 

258    06  02  .1 

170    53  52  .0 

8  Ceres, 

1848  March,  12.0 

21    04  00  .5 

80   47    17  .9 

9  Pallas, 

1848  March,    4.0 

24    57  23  .4 

172    42   12  .3 

ELEMENTS, — Continued, 


Long  asc.  node.  —  Long. 

Names. 

of  Perihelion. 

Inclination. 

Ang.  of  Eccentricity. 

I   Flora, 

77°  26'  49".  1 

50  52'  55".9 

9°  01'  36".9 

2  Vesta, 

212    16   14  .4 

7    08  30  .3 

5    07  21  .5 

3  Iris, 

218    18  35  .6 

5    28  10  .9 

13    20  50  .1 

4   Metis, 

4    20  27  .7 

5    35  24  .0 

7    13  36  .9 

5  Hebe, 

123    36  42  .1 

14    44  25  .3 

11    31    11  .4 

6  Astrea, 

6    00  31  .4 

5    19  17  .1 

10    49  55  .6 

7  Juno, 

116    35  04  .0 

13    02  39  .3 

14    42   19  .6 

8  Ceres, 

293    28  14  .7 

10    37  13  .1 

4    24  56  .8 

9  Pallas, 

51     26  35  .1 

34    37  31  .1 

13    54  48  .9 

Y2 


Names. 

1  Flora, 

2  Vesta, 

3  Iris, 

4  Metis, 

5  Hebe, 

6  Astrea, 

7  Juno, 

8  Ceres, 

9  Pallas, 


Mean  daily  Sid.  mo. 
1086". II 00 
977  .948 
963  .4498 
962  .5660 
942  .3754 
857  .8493 
812  .7012 
770  .9866 
768  .8858 


270  GEOGRAPHY  OF   THE   HEAVENS. 

From  these  elements  and  data,  some  curious  results  may  be  obtained 
with  reference  to  the  orbits  of  eight  of  the  asteroids.  The  last  discovered, 
Metis,  is  not  yet  sufficiently  known  to  include  it  in  these  examinations. 

There  are  ten  cases  where  the  orbits  are  entirely  enclosed  the  one 
within  the  other,  viz. 

Flora  in  Hebe. 

Iris  and  Flora  in  Juno. 

Astrea  and  Vesta  in  Pallas. 

Iris,  Flora,  Pallas,  Astrea  and  Vesta  in  Ceres. 

The  following  orbits  interlock  like  the  links  of  a  chain,  viz. 


Hebe  and  Astrea. 
Juno  and  Astrea. 
Vesta  and  Astrea. 
Flora  and  Astrea. 
Iris  and  Astrea. 
Pallas  in  Iris. 

Hebe  and  Iris. 
Vesta  and  Iris. 
Flora  and  Iris. 
Pallas  and  Juno. 
Vesta  and  Juno. 
Hebe  and  Juno. 

Ceres  and  Juno. 
Pallas  and  Hebe. 
Vesta  and  Hebe. 
Ceres  and  Hebe. 
Pallas  in  Flora. 
Vesta  in  Flora. 

In  those  cases  where  the  orbits  interlock  with  each  other,  as  the  nodes 
of  one  orbit  on  any  other  are  perpetually  shifting,  the  time  may  come 
when  an  actual  intersection  of  the  orbits  may  take  place.  If  at  such  a 
time  the  two  planets  should  be  found  at  the  same  time  in  this  now  com- 
mon point  of  their  orbits,  a  collision  would  take  place,  which,  in  conse- 
quence of  the  probable  rotary  motion  of  the  moving  bodies,  would  pro- 
duce a  sudden  and  terrific  shock.  The  very  near  equality  of  the  orbital 
motions  would  secure  the  planets  from  any  severe  collision  from  their 
velocities  in  their  orbits. 

If  the  knowledge  of  these  minute  planets  was  perfect,  it  would  not  be 
impossible  to  compute  backward  or  forward  and  ascertain  the  time 
when  the  orbits  of  any  pair  actually  intersected  each  other,  and  where  the 
planets  were  at  the  time  of  this  intersection.  Could  the  interval-  between 
the  times  of  intersection  be  obtained,  combining  these  with  the  periods  of 
the  asteroids  in  their  orbits,  it  would  become  possible  to  compute  the  time 
when  a  collision  of  the  planets  is  to  take  place. 

By  computations  Encke  found  that  about  the  year  A.  D.  3397,  the 
orbit  of  Ceres  would  actually  cut  the  orbit  of  Pallas ;  but  to  obtain  the 
positions  of  the  planets  in  their  orbits,  at  the  time  of  intersection,  has  not 
been  attempted. 

The  hypothesis  of  Olbers  gathers  strength  from  every  new  asteroid  dis- 
covered, although  the  fact  that  the  aphelion  of  Flora  is  shorter  than  the 
perihelion  of  Ceres,  presents  a  difficulty  which  had  not  before  existed. 


JUPITER. 

JUPITER  is  the  largest  of  all  the  planets  belonging  to  the  solai 
system.  It  may  be  readily  distinguished  from  the  fixed  stars, 
by  its  peculiar  splendor  and  magnitude ;  appearing  to  the  naked 


JUPITER.  271 

eye  almost  as  rtsplendent  as  Venus,  although  it  is  more  than 
seven  times  her  distance  from  the  sun. 

When  his  right  ascension  is  less  than  that  of  the  sun,  he  is 
our  morning  star,  and  appears  in  the  eastern  hemisphere  before 
the  sun  rises ;  when  greater,  he  is  our  evening  star,  and  lingers 
in  the  western  hemisphere  after  the  sun  sets. 

Nothing  can  be  easier  than  to  trace  Jupiter  among  the  con- 
stellations of  the  zodiac;  for  in  whatever  constellation  he  is  seen 
to-day,  one  year  hence  he  will  be  seen  equally  advanced  in  the 
next  constellation ;  two  years  hence,  in  the  next;  three  years 
hence,  in  the  next,  and  so  on ;  being  just  a  year,  at  a  mean  rate, 
in  passing  over  one  constellation. 

The  exact  mean  motion  of  Jupiter  in  its  orbit,  is  about  one  twelfth  of 
a  degree  in  a  day ;  which  amounts  to  only  30°  20'  32"  in  a  year. 

Jupiter  is  the  next  planet  in  the  solar  system  above  the  aste- 
roids, and  performs  his  annual  revolution  around  the  sun  in  nearly 
12  of  our  years,  at  the  mean  distance  of  495  millions  of  miles ; 
moving  in  his  orbit  at  the  rate  of  30,000  miles  an  hour. 

The  exact  period  of  Jupiter's  sidereal  revolution  is  1 1  years,  1 0  months, 
17  days,  14  hours,  21  minutes,  25£  seconds.  His  exact  mean  distance 
from  the  sun  is  495,533,837  miles ;  consequently,  the  exact  rate  of  his 
motion  in  his  orbit,  is  29,943  miles  per  hour. 

He  revolves  on  an  axis,  which  is  perpendicular  to  the  plane 
of  his  orbit,  in  9  hours,  55  minutes,  and  50  seconds;  so  that  his 
year  contains  10,471  days  and  nights;  each  about  5  hours  long. 

His  form  is  that  of  an  oblate  spheroid,  whose  polar  diameter 
is  to  its  equatorial,  as  13  to  14.  He  is  therefore  considerably 
more  flattened  at  the  poles,  than  any  of  the  other  planets,  except 
Saturn.  This  is  caused  by  his  rapid  rotation  on  his  axis ;  for  it 
is  a  universal  law,  that  the  equatorial  parts  of  every  body  revolv- 
ing on  an  axis,  will  be  swollen  out  in  proportion  to  the  density 
of  the  body,  and  the  rapidity  of  its  motion. 

The  difference  between  the  polar  and  equatorial  diameters  of  Jupiter, 
exceeds  6000  miles.  The  difference  between  the  polar  and  equatorial 
diameters  of  the  earth,  is  only  26  miles.  Jupiter,  even  on  the  most  care- 
Jess  view  through  a  good  telescope,  appears  to  be  oval ;  the  longer  diame- 
ter being  parallel  to  the  direction  of  his  belts,  which  are  also  parallel  to 
the  ecliptic. 

By  this  rapid  whirl  on  his  axis,  his  equatorial  inhabitants  are 
carried  around  at  the  rate  of  26,554  miles  an  hour;  which  ia 
1600  miles  farther  than  the  equatorial  inhabitants  of  the  earth 
are  carried,  by  its  diurnal  motion,  in  twenty-four  hours. 

The  true  mean  diameter  of  Jupiter  is  86,255  miles;  which  is 
nearly  11  times  greater  than  the  earth's.  His  volume  is,  there- 


272  GEOGRAPHY  OF  THE  HEAVENS. 

fore,  about  thirteen  hundred  miles  larger  than  that  of  the  earth. 
On  account  o£  his  great  distance  from  the  sun,  the  degree  of 
light  and  heat  which  he  receives  from  it,  is  27  times  less  than 
that  received  by  the  earth. 

When  Jupiter  is  in  conjunction,  he  rises,  sets,  and  comes  to  the  meri- 
dian with  the  sun ;  but  is  never  observed  to  make  a  transit,  or  pass  over 
the  sun's  disk ;  when  in  opposition,  he  rises  when  the  sun  sets,  sets  when 
the  sun  rises,  and  comes  to  the  meridian  at  midnight,  which  never  hap- 
pens in  the  case  of  an  interior  planet.  This  proves  that  Jupiter  revolves 
in  an  orbit  which  is  exterior  to  that  of  the  earth. 

As  the  variety  in  the  seasons  of  a  planet,  and  in  the  length  of 
its  days  and  nights,  depends  upon  the  inclination  of  its  axis  to 
the  plane  of  its  orbit,  and  as  the  axis  of  Jupiter  has  no  inclina- 
tion, there  can  be  no  difference  in  his  seasons,  op- the  same  par- 
allels of  latitude,  nor  any  variation  in  the  length  of  his  days  and 
nights.  It  is  not  to  be  understood,  however,  that  one  uniform 
season  prevails  from  his  equator  to  his  poles;  but  that  the  same 
parallels  of  latitude  on  each  side  of  his  equator,  uniformly  enjoy 
the  same  season,  whatever  season  it  may  be. 

About  his  equatorial  regions,  there  is  perpetual  summer;  and 
at  his  poles,  everlasting  winter;  but  yet  equal  day  and  equal 
night  at  each.  This  arrangement  seems  to  have  been  kindly  or- 
dered by  the  beneficent  Creator;  for  had  his  axis  been  inclined 
to  his  orbit,  like  that  of  the  earth,  his  polar  winters  would  have 
been  alternately  a  dreadful  night  of  six  years  darkness. 

Jupiter,  when  viewed  through  a 'telescope,  appears  to  be  sur- 
rounded by  a  number  of  luminous  zones,  usually  termed  belts, 
that  frequently  extend  quite  around  him.  These  belts  are  parallel 
not  only  to  each  other,  but,  in  general,  to  his  equator,  which  is 
also  nearly  parallel  to  the  ecliptic.  They  are  subject,  however, 
to  considerable  variation,  both  in  breadth  and  number.  Some- 
times eight  have  been  seen  at  once ;  sometimes  only  one,  but 
more  usually  three.  Dr.  Herschel  once  perceived  his  whole 
disk  covered  with  small  belts. 

Sometimes  these  belts  continue  for  months  at  a  time  with 
little  or  no  variation,  and  sometimes  a  new  belt  has  been  seen 
to  form  in  a  few  hours.  Sometimes  they  are  interrupted  in  their 
length;  and  at  other  times,  they  appear  to  spread  in  width,  and 
run  into  each  other,  until  their  breadth  exceeds  5,000  miles. 

Bright  and  dark  spots  are  also  frequently  to  be  seen  in  the 
belts,  which  usually  disappear  with  the  belts  themselves,  though 
not  always,  for  Cassini  observed  that  one  occupied  the  same 
position  more  than  40  years.  Of  the  cause  of  these  variable 
appearances,  but  little  is  known.  They  are  generally  supposed 
to  be  nothing  more  than  atmospherical  phenomena,  resulting  from, 
or  combined  with,  the  rapid  motion  of  the  planet  upon  its  axis. 


JUPITER.  273 

Different  opinions  have  been  entertained  by  astronomers  respecting  the 
cause  of  these  belts  and  spots.  By  some  they  have  been  regarded  as 
clouds  or  as  openings  in  the  atmosphere  of  the  planet,  while  others  ima- 
gine that  they  are  of  a  more  permanent  nature,  and  are  the  marks  of 
great  physical  revolutions,  which  are  perpetually  agitating  and  changing 
the  surface  of  the  planet.  The  first  of  these  opinions  sufficiently  ex- 
plains the  variations  in  the  form  and  magnitude  of  the  spot*,  and  the 
parallelism  of  the  belts.  The  spot  first  observed  by  Cassini,  in  1  (iH5, 
which  has  both  disappeared  and  reappeared  in  the  same  form  and  posi- 
tion for  the  space  of  43  years,  could  not  possibly  be  occasioned  by  any 
atmospherical  variations,  but  seems  evidently  to  be  connected  with  the 
surface  of  the  planet.  The  form  of  the  belt,  according  to  some  astrono- 
mers, may  be  accounted  for  by  supposing  that  the  atmosphere  reflects 
more  light  than  the  body  of  the  planet,  and  that  the  clouds  which  float  in 
it,  being  thrown  into  parallel  strata  by  the  rapidity  of  its  diurnal  motion, 
form  regular  interstices,  through  which  are  seen  its  opake  body,  or  any 
of  the  permanent  spots  which  may  come  within  the  range  of  the  opening. 

Jupiter  is  also  attended  by  four  satellites  or  moons,  some  of 
which  are  visible  to  him  every  hour  of  the  night;  exhibiting1,  on 
a  small  scale  and  in  short  periods,  most  of  the  phenomena  of  the 
solar  system.  When  viewed  through  a  telescope,  these  satel- 
lites present  a  most  interesting  and  beautiful  appearance.  The 
first  satellite,  or  that  nearest  the  planet,  is  259,000  miles  distant 
from  its  center,  and  revolves  around  it  in  42^  hours ;  and  appears, 
at  the  surface  of  Jupiter,  four  times  larger  than  our  moon  does 
to  us.  His  second  satellite,  being  both  smaller  and  farther  dis- 
tant, appears  about  the  size  of  ours  ;  the  third,  somewhat  less ; 
and  the  fourth,  which  is  more  than  a  million  of  miles  from  him, 
and  takes  16f  days  to  revolve  around  him,  appears  only  about 
one  third  the  diameter  of  our  moon. 

These  satellites  suffer  frequent  eclipses  from  passing  through 
Jupiter's  shadow ;  in  the  same  manner  as  our  moon  is  eclipsed 
in  passing  through  the  earth's  shadow.  The  three  nearest  sa- 
tellites fall  into  his  shadow,  and  are  eclipsed,  in  every  revolu- 
tion; but  the  orbit  of  the  fourth  is  so  much  inclined,  that  it 
passes  by  its  opposition  to  him,  two  years  in  six,  without  fall- 
ing into  his  shadow.  By  means  of  these  eclipses,  astronomers 
have  not  only  discovered  that  light  is  8  minutes  and  13  seconds 
in  coming  to  us  from  the  sun,  but  are  also  enabled  to  determine 
the  longitude  of  places  on  the  earth  with  greater  facility  and 
exactness  than  by  any  other  methods  yet  known. 

It  was  long  since  found,  by  the  most  careful  observations,  that  when 
the  earth  is  in  that  part  of  her  orbit  which  is  nearest  to  Jupiter,  the 
eclipses  appear  to  happen  8'  13"  sooner  than  the  tables  predict;  and 
when  in  that  part  of  her  orbit  which  is  farthest  from  him.  8'  13"  later 
than  the  tables  predict;  making  a  total  difference  hi  time,  of  16'  26". 
From  the  mean  of  6000  eclipses  observed  by  Delambre,  this  disagreement 


^74  GEOGRAPHY  OF  THE  HEAVENS. 

between  observation  and  calculation,  was  satisfactorily  settled  at  8'  13", 
while  both  were  considered  equally  correct.  Now,  when  the  eclipses 
happen  sooner  than  the  tables,  Jupiter  is  at  his  nearest  approach  to  the 
earth — when  later,  at  his  greatest  distance  ;  so  that  the  difference  in  his 
distances  from  the  earth,  in  the  two  cases,  is  the  whole  diameter  of  the 
earth's  orbit,  or  about  190  millions  of  miles.  Hence,  it  is  concluded  that 
light  is  not  instantaneous,  but  that  it  occupies  16'  26"  in  passing  across 
the  earth's  orbit,  or  8'  13"  in  coming  from  the  sun  to  the  earth  ;  being 
nearly  12  millions  of  miles  a  minute. 

The  revolutions  of  the  satellites  about  Jupiter  are  precisely 
similar  to  the  revolutions  of  the  planets  about  the  sun.  In  this 
respect  they  are  an  epitome  of  the  solar  system,  exhibiting,  on 
a  smaller  scale,  the  various  changes  that  take  place  among  the 
planetary  worlds. 

Jupiter,  when  seen  from  his  nearest  satellite,  appears  a  thou- 
sand times  larger  than  our  moon  does  to  us,  exhibiting  on  a  scale 
of  inconceivable  magnificence,  the  varying  forms  of  a  crescent, 
a  half  moon,  a  gibbous  phase,  and  a  full  moon,  every  forty-two 
hours. 

Elements  of  Jupiter  and  his  satellites  for  Jan  1st,  1801. 

PLANET. 

Mean  sid.  revolu.  (nearly  12  years),  solar  days,    4332d.  14h.02m.  08.5s. 

Mean  synodic  rev.  solar  days,  -  -  398.867 
Mean  longitude,  -  -  1 12°  1 5' 23".  0 

Mean  orbital  mo.  in  a  solar  day,              •                  -  4  59  .26 

Do.  per  annum,                           -                  -  30    20  32  .0 

Longitude  of  perihelion,                          -                  -  11    08  34  .6 

Annual  mo.  of  apsides  eastward,  -                  -  6  .96 

Do.  referred  to  the  ecliptic,                   -                  -  57  .06 

Inclination  of  orbit  to  the  ecliptic,                     -  1    18  51  .3 

Annual  decrease  of  do.                           •                   •  0  .226 

Longitude  of  ascending  node          -              .<.ifc  ;»  98    26  18  .9 

Motion  of  do.  west  per  annum,         ..   ^fc              •  15   .8 

Ditto  east,  referred  to  the  ecliptic,  -                  -  34  .3 

Eccentricity  of  orbit,  half  maj.  axis  unity,                -  0.0481621 

Increase  of  ditto  in  a  century,                          •  0.000159350 

Greatest  equation  of  center,                                       -  5°  31'  13".  8 

Annual  increase  of  ditto,                      -  0  .634 

Rotation  on  axis,                                                        -  9h.  55m.  49.7s. 

Inclination  of  axis  to  ecliptic,               -            -  3°  05'  30".  0 

Mean  apparent  eq.  diam.          -                                -  36  .74 

Ditto  at  conjunction,               -                         -            -  30  .00 

Ditto  at  opposition                -                     -            -  45  . 88 
True  diam.  (90,000  miles  nearly)  earth's  diam.  unity,      -          10  .860 

Volume,  earth's  as  unity,             -            .•;.       '  '  -  ',  '  1280.9 

Mass,  sun's  as  unity,            .             -        '    j,.^     J.  0.0009341431 

Density,  sun's  as  unity,              ...  .            0.99239 

Mean  distance  (485,000,000  miles),  earth's  as  unity,    -  '  5.202776 


JUPITER. 


275 


ELEMENTS. 


SATELLITES. 


First. 

Second. 

Third. 

Fourth. 

Sid.  rev.  in  m.  solar  days. 
Ditto  for  computation, 
Mean  app.  diam. 
Ditto  in  miles. 
Mass,  Jup.  as  one. 
M.  dist.  Jup.  eq.  rad.  as  1. 
Ditto  in  degrees, 
Ditto  in  miles, 

Id.  1  8h.  28m. 
1  .7691378 
1".015 
2508 
0.0000173 
6.01853 
0°1'57".92 
260,000 

3d.  13h.  14m. 
3  .5518101 
0".9I1 
2068 
0.0000232 
9.62347 
0°  3'  07".64 
420,000 

7d.  3h.43m. 
7    1545528 
1".488 
3377 
0.0000885 
15  35024 
0°  04'  59".32 
670,000 

16d.  16h.  :>2m. 
16   688769? 
1".273 
2890 
0.01,00427 
26.90835 
0°  8'  4(i".48 
1.180.000 

A  most  curious  phenomenon  with  reference  to  one  of  the  satellites  of 
Jupiter,  has  recently  been  observed  at  the  Cambridge  observatory,  and 
also  at  the  Cincinnati  observatory.  In  passing  across  the  disk  of  the 
planet,  it  has  been  seen  to  lose  its  light  as  if  undergoing  eclipse,  until  it 
finally  becomes  a  black  spot  on  the  disk  of  the  planet ;  after  passing  off 
the  disk  it  resumes  its  light 


SATURN. 

SATURN  is  situated  between  the  orbits  of  Jupiter  and  Herschel, 
and  is  the  most  remote  planet  from  the  earth  of  any  that  are 
visible  to  the  naked,  eye.  It  may  be  easily  distinguished  from 
the  fixed  stars  by  its  pale,  feeble,  and  steady  light.  It  resembles 
the  star  Fomalhaut,  both  in  color  and  size,  differing  from  it  only 
in  the  steadiness  and  uniformity  of  its  light. 

From  the  slowness  of  its  motion  in  its  orbit,  the  pupil,  through- 
out the  period  of  his  whole  life,  may  trace  its  apparent  course 
among  the  stars,  without  any  danger  of  mistake.  Having  once 
found  when  it  enters  a  particular  constellation,  he  may  easily 
remember  where  he  is  to  look  for  it  in  any  subsequent  year ; 
because,  at  a  mean  rate,  it  is  just  two  and  a  half  years  in  pass- 
ing over  a  single  sign  or  constellation. 

Saturn's  mean  daily  motion  among  the  stars  is  only  about  2', 
the  thirtieth  part  of  a  degree. 

Saturn  entered  the  constellation  Virgo  about  the  beginning  of  1833, 
and  continued  in  it  until  the  middle  of  the  year  1835,  when  he  passed 
into  Libra,  He  will  continue  in  that  constellation  until  1838 ;  and  so 
on. ;  occupying  about  2£  years  in  each  constellation,  or  nearly  thirty  years 
in  one  revolution. 

The  mean  distance  of  Saturn  from  the  sun  is  nearly  double  that 
of  Jupiter,  being  about  nine  hundred  and  nine  millions  of  miles. 
His  diameter  is  about  82,000  miles  ;  his  volume  therefore  is 
eleven  hundred  times  greater  than  the  earth's.  Moving  in  his 
orbit  at  the  rate  of  22,000  miles  an  hour,  he  requires  twenty- 
nine  and  a  half  years  to  complete  his  circuit  around  the  sun  : 


276        GEOGRAPHY  OF  THE  HEAVENS. 

but  his  diurnal  rotation  on  his  axis  is  accomplished  in  ten  and  a 
half  hours.  His  year,  therefore,  is  nearly  thirty  times  as  long 
as  ours,  while  his  day  is  shorter  by  more  than  one  half.  His 
year  contains  about  25,150  of  its  own  days,  which  are  equal  to 
10,759  of  our  days. 

The  surface  of  Saturn,  like  that  of  Jupiter,  is  diversified  with 
belts  and  dark  spots.  Dr.  Herschel  sometimes  perceived  five 
belts  on  his  surface ;  three  of  which  were  dark,  and  two  bright. 
The  dark  belts  have  a  yellowish  tinge,  and  generally  cover  a 
broader  zone  of  the  planet  than  those  of  Jupiter. 

To  the  inhabitants  of  Saturn,  the  sun  appears  ninety  times 
less  than  he  appears  to  the  earth ;  and  they  receive  from  him 
only  one  ninetieth  part  as  much  light  and  heat.  But  it  is  com- 
puted that  even  the  ninetieth  part  of  the  sun's  light  exceeds  the 
illuminating  power  of  3,000  full  moons,  which  would  be  abun- 
dantly sufficient  for  all  the  purposes  of  life. 

The  telescopic  appearance  of  Saturn  is  unparalleled.  It  is 
even  more  interesting  than  Jupiter,  with  all  his  moons  and  belts. 
That  which  eminently  distinguishes  this  planet  from  every  other 
in  the  system,  is  a  magnificent  zone  or  ring,  encircling  it  with 
perpetual  light. 

The  light  of  the  ring  is  more  brilliant  than  the  planet  itself. 
It  turns  around  its  center  of  motion  in  the  same  time  that  Saturn 
turns  on  its  axis.  When  viewed  with  a  good  telescope,  it  is 
found  to  consist  of  two  concentric  rings,  divided  by  a  dark  band. 

By  the  laws  of  mechanics,  it  is  impossible  that  the  body  of  the  rings 
should  retain  its  position  by  the  adhesion  of  the  particles  alone ;  it  must 
necessarily  revolve  with  a  velocity  that  will  generate  centrifugal  force  suf- 
ficient to  balance  the  attraction  of  Saturn.  Observation  confirms  the 
truth  of  these  principles,  showing  that  the  rings  rotate  about  the  planet 
in  I0j  hours,  which  is  considerably  less  than  the  time  a  satellite  would 
take  to  revolve  about  it  at  the  same  distance.  Their  plane  is  inclined  to 
the  ecliptic  in  an  angle  of  31°.  In  consequence  of  this  obliquity  of 
position,  they  always  appear  elliptical  to  us,  but  with  an  eccentricity  so 
variable  as  to  appear,  occasionally,  like  a  straight  line  drawn  across  the 
planet ;  hi  which  case  they  are  visible  only  by  the  aid  of  superior  instru- 
ments. Such  was  their  position  in  April,  1833  ;  for  the  sun  was  then 
passing  from  their  south  to  their  north  side.  The  rings  intersect  the  eclip- 
tic in  two  opposite  points,  which  may  be  called  their  nodes.  These  points 
are  in  longitude  1 70°,  and  350°.  When,  therefore,  Saturn  is  in  either  of 
these  points,  his  rings  will  be  invisible  to  us.  On  the  contrary,  when 
his  longitude  is  80°,  or  200°,  the  rings  may  be  seen  to  the  greatest  advan- 
tage. As  the  edges  of  the  rings  will  present  themselves  to  the  sun  twice 
in  each  revolution  of  the  planet,  it  is  obvious  that  the  disappearance  of 
them  will  occur  once  in  about  1 5  years ;  subject,  however,  to  the  varia- 
tion dependent  on  the  position  of  the  earth  at  that  time. 

The  following  are  the  dates  during  the  ensuing  revolutions  of  the 
planet,  when  its  mean  heliocentric  longitude  is  such  that  the  rings  will  (if 


SATURN.  277 

the  earth  be  favorably  situated),  either  be  invisible,  or  seen  to  the  greatest 
advantage. 

1838  July,  200  of  Scorpio,  North  side  illuminated 

1847  Dec.  20°  of  Aquarius,  Invisible, 

i  855  April,  20°  of  Gemini,  South  side  illuminated. 

1863  Nov.  20°  of  Virgo,  Invisible. 

The  distance  between  Saturn  and  his  inner  ring,  is  only 
21,000  miles;  being  less  than  a  tenth  part  of  the  distance  of 
our  moon  from  the  earth.  The  breadth  of  the  dark  band,  or  the 
interval  between  the  rings,  is  hardly  3,000  miles.— The  breadth 
of  the  inner  ring,  is  20,000  miles.  Being  only  about  the  same 
distance  from  Saturn,  it  will  present  to  his  inhabitants  a  lumin- 
ous zone,  arching  the  whole  concave  vault  from  one  hemisphere 
to  the  other  with  a  broad  girdle  of  light. 

The  most  obvious  use  of  this  double  ring  is,  to  reflect  light  upon 
the  planet  in  the  absence  of  the  sun;  what  other  purposes1!!  may 
be  intended  to  subserve,  is  to  us  unknown.  The  sun,  as  has 
been  shown,  illuminates  one  side  of  it  during  15  years,  or  one 
half  of  the  period  of  the  planet's  revolution;  and  during  the 
next  15  years,  the  other  side  is  enlightened  in  its  turn. 

Twice  in  the  course  of  30  years,  there  is  a 'short  interval  of 
time  when  neither  side  is  enlightened,  and  when,  of  course,  it 
ceases  to  be  visible; — namely,  at  the  time  when  the  sun  ceases 
to  shine  on  one  side,  and  is  about  to  shine  on  the  other.*  Ii 
revolves  around  its  axis,  and  consequently,  around  Saturn,  in 
10^°  hours,  which  is  at  the  rate  of  a  thousand  miles  a  minute, 
or  58  times  swifter  than  the  revolution  of  th«  earth's  equator. 

When  viewed  from  the  middle  zone  of  the  planet,  in  the 
absence  of  the  sun,  the  rings  will  appear  like  vast  luminous 
arches,  extending  along  the  canopy  of  heaven,  from  the  eastern 
to  the  western  horizon,  exceeding  in  breadth  a  hundred  times  the 
apparent  diameter  of  our  moon. 

Besides  the  rings,  Saturn  is  attended  by  seven  satellites, 
which  revolve  about  him  at  different  periods  and  distances,  and 
reciprocally  reflect  the  sun's  rays  on  each  other  and  on  the 
planet.  The  rings  and  moons  illuminate  the  nights  of  Saturn  ; 
the  moons  and  Saturn  enlighten  the  rings,  and  the  planet  and 
rings  reflect  the  sun's  beams  on  the  satellites. 

The  fourth  of  these  satellites  (in  the  order  of  their  distance)  was  first 
discovered  by  Huygens.  on  the  25th  of  March,  1655,  and,  in  honor  of 

*  This  happens,  as  we  have  already  shown,  when  Saturn  is  either  in  the  20th 
decree  of  Pisces,  or  the  20th  degree  of  Virgo.  When  he  is  between  these 
points,  or  in  the  20th  degree  either  of  Gemini  or  of  Sagittarius,  his  ring  appears 
most  open  to  us,  and  more  in  the  form  of  au  oval,  whose  longest  diameter  is  to 
the  shortest  as  9  to  4. 

z 


278  GEOGRAPHY  OF  THE  HEAVENS. 

the  discoverer,  was  called  the  Huygenian  Satellite.  This  satellite,  being 
the  largest  of  all,  is  seen  without  much  difficulty.  Cassini  discovered  the 
1st,  2d,  3d,  and  5th  satellites,  between  October,  1671,  and  March,  1684. 
Dr.  Herschel  discovered  the  6th  and  7th  in  1789.  These  are  nearer  to 
Saturn  than  any  of  the  rest,  though,  o  avoid  confusion,  they  are  named 
in  the  order  of  their  discovery. 

The  sixth  and  seventh  are  the  smallest  of  the  whole ;  the  first 
and  second  are  the  next  smallest;  the  third  is  greater  than  the 
first  and  second  ;  the  fourth  is  the  largest  of  them  all ;  and  the 
fifth  surpasses  the  rest  in  brightness. 

Their  respective  distances  from  their  primary,  vary  from  half 
the  distance  of  our  moon,  to  two  millions  of  miles.  Their  pe- 
riodic revolutions  vary  from  1  day  to  79  days.  The  orbits  of 
the  six  inner  satellites,  that  is,  the  1st,  2d,  3d,  4th,  6th,  and  7th, 
all  lie  in  the  plane  of  Saturn's  rings,  and  revolve  around  their 
outer  edge ;  while  the  5th  satellite  deviates  so  far  from  the  plane 
of"  the^rings,  as  sometimes  to  be  seen  through  the  opening  between 
them  and  the  planet. 

Laplace  imagines  that  the  accumulation  of  matter  at  Saturn's  equator 
retains  the  orbits  of  the  first  six  satellites  in  the  plane  of  the  equator,  in 
the  same  manner  as  it  retains  the  rings  in  that  plane.  It  has  been  satis- 
factorily ascertained,  that  Saturn  has  a  greater  accumulation  of  matter 
about  his  equator,  and  consequently  that  he  is  more  flattened  at  the 
poles,  than  Jupiter,  though  the  velocity  of  the  equatorial  parts  of  the  for- 
mer is  much  less  than  that  of  the  latter.  This  is  sufficiently  accounted 
for  by  the  fact,  that  the  rin^s  of  Saturn  lie  in  the  plane  of  his  equator, 
and  act  more  powerfully  upon  those  parts  of  his  surface  than  upon  any 
other;  and  thus,  white  they  aid  in  diminishing  the  gravity  of  these  parts, 
also  aid  the  centrifugal  force  in  flattening  the  poles  of  the  planet.  Indeed, 
had  Saturn  never  revolved  upon  his  axis,  the  action  of  the  rings  would, 
of  itself,  have  been  sufficient  to  give  him  the  form  of  an  oblate  spheroid. 
Saturnian  elements,  January  1,  1801 : 

Mean  distance  (about  890,000,000  miles),  earth's  as  one,     9.538786 
Mean  sid.  rev.  (29,456  years),  mean  solar  days,  -  10759.2198 

Mean  synod,  rev.  in  mean  solar  days,  -  -  378.090 

Mean  longitude,  -  -  -  135°  20'  06".5 

Mean  orbital  motion  in  a  mean  solar  day,  2'  00".  6 

Do.  in  a  solar  year,      V"         -  -  -       12°  13'  36".  1 

Longitude  of  perihelion,         -  -  -  89°  09>  29".  8 

Ann.  mo.  of  apsides  eastward,      •  •  ...         19".4 

Ditto  referred  to  ecliptic,         -  -  -  -  1'  09".5 

Inclination  of  orbit  to  ecliptic,       ...          2°  29'  35".7 
Annual  decrease  of  ditto,       -  -  .         •  »*  0".155 

Long,  of  ascend,  node,     ....      111°  56' 37".40 
Motion  of        do.         per  an.  west,    -  -  -  -    1 9".4 

«        «  "          «      «    east,  ref.  to  ecliptic,  -         30".  7 

Eccentricity  half  maj.  axis  unity,        -  -  -.      0.0561505 


SATURN. 


279 


Decrease  of  do.  in  a  century,        -       J    •       .     -          0.000312402 
Greatest  equation  of  center,    -        ,,«!*'  !•  >  '        -  6°  26'  12".00 

Annual  decrease  of       do.  .«_-• *.-",          -  '«        1".279 

Rotation  on  axis,       -  ...        10  h.  29  m.  16.8  s. 

Inclination  of  axis  to  ecliptic,        -  -        •'   «    '  31°  19' 

App.  diam.  at  mean  dist.  from  the  earth,         -        |     *,  16".20 

True  diam.  (about  70068  miles),  earth's  as  unity,  -         9.982 

Volume,  earth's  as  unity,        -  *  Mj        -  -  995.00 

Mass,  sun's  as  unity,        -  -        ,  *  •  •  -        0.0002847380 

Density,  sun's  as  unity,          ....  0.5.^0 


THE    RINGS. 

Miles. 

Outer  diam.  of  exterior  ring,        -  40".095  -  176.418 

Inner      "      «         «         «                   -  35  .289  -  155.272 

Outer  diam.  of  inner  ring,            -  34.475  -  151.690 

Inner      "      «         «         «                   -  26  .668  -  117.339 

Equat.  diam.  of  planet.    -            -  17.991  -  79.160 

Breadth  of  division  between  the  rings,  0  .408  •  1.791 

Dist.  of  ring  from  the  planet,       -  4  .339  -  19.090 

The  multiple  division  of  Saturn's  rings  has  been  a  matter  of  some 
dispute.  There  now  seems  little  doubt  that  the  exterior  ring  is-  divided 
into  two  rings.  Prof.  Encke  saw  the  division  distinctly,  April  25,  1837. 
On  the  25th  of  May  he  obtained  these  approximate  measures : 


Outer  diam.  of  ext.  ring, 

"         "      "  new  division, 
Inner  diam.  of  outer  ring,    - 
Outer  diam.  of  inner  ring, 
Inner  diam.  of  inner  ring,    • 


40".  455 
37  .471 
36  .038 
34  .749 
26  .756 


These  are  the  only  measures  which  I  have  seen.  The  third  division 
was  distinctly  observed  on  the  7th  September,.  1843,  at  Mr.  Lassell's 
observatory,  near  Liverpool.  Since  the  erection  of  the  Refractor  of  the 
Cincinnati  Observatory,  the  planes  of  Saturn's  rings  have  been  too  much 
inclined  to  the  visual  ray  for  exact  examination.  I  have  never  been  able 
to  make  out  the  triple  division  of  the  rings. 

It  has  been  found  that  the  laws  of  perfect  equilibrium  require  that  the 
center  of  the  rings  should  not  coincide  with  the  center  of  the  planet 
Exact  measures  have  shown  that  this  discovery  of  theory  is  verified  in 
nature.  There  is  a  slight  difference  in  the  respective  distances  from  the 
planet  to  the  inner  edge  of  the  ring  on  the  right  and  left,  amounting 
to  about  two-tenths  of  a  second  of  arc. 

Saturn  is  one  of  the  most  magnificent  objects  in  the  heavens,  when 
seen  with  a  powerful  telescope,  and  never  fails  to  excite  the  most  pro- 
found admiration  in  the  beholder. 

The  satellites  of  Saturn  are  by  no  means  as  well  known  as  those  of 
Jupiter.  The  two  inner  satellites  are  among  the  most  difficult  objects  to 
be  seen  in  the  heavens.  The  following  elements  may  be  regarded  as  a 
near  approximation  to  the  truth. 


280 


GEOGRAPHY  OF  THE  HEAVENS. 


Satellite. 

Sidereal 
Revolution 
in  mean 
Solar  Day. 

Mean  Distance. 

Discoverer  and 
Date. 

Order 
from 
Planet 

Old 
Order. 

Saturn's 
Radius  as 
unity. 

Angle  sub- 
tended. 

Miles. 

I 
II 
III 

IV 
V 
VI 
VII 

7 

6 
1 
2 
3 
4 
5 

d.    h.  m. 
0  22  38 
1  08  53 
1  21    18 
2  17  45 
4  12  25 
15  22  41 
79  07  55 

3.351 
4.300 
5.284 
6.819 
9.524 
22.081 
64.359 

29.15 
31.19 
45.13 
1   0093 
1  24.86 
3  26.50 
9  28.00 

120,000 
150,000 
190,000 
243,000 
340,000 
788,000 
2,297,000 

W.  Herschel,  1789 
D.  Cassini,  .  1684 

a            «                   <t 

U                 (I                          « 

C.  Huygens,   1655 
D.  Cassini,   .1671 

URANUS  OR  HERSCHEL. 

URANUS  is  the  planet  next  beyond  Saturn ;  to  the  naked  eye, 
it  appears  like  a  star  of  only  the  sixth  or  seventh  magnitude, 
and  of 'a  pale,  bluish  white;  but  it  can  seldom  be  seen,  except 
in  a  very  fine,  clear  night,  and  in  the  absence  of  the  moon. 

As  it  moves  over  but  one  degree  of  its  orbit  in  eighty-five  days, 
it  will  be  seven  years  in  passing  over  one  sign  or  constellation. 

When  first  seen  by  Dr.  Herschel,  in  1781,  it  was  in  the  foot 
of  Gemini  ,-  so  that  it  has  not  yet  completed  one  revolution  since  it 
was  discovered  to  be  a  planet. 

It  is  remarkable  that  this  body  was  observed  as  far  back  as  1 690.  It 
was  seen  three  times  by  Flamstead,  once  by  Bradley,  once  by  Mayer,  and 
eleven  times  by  Lemonnier,  who  registered  it  among  the  stars ;  but  not 
one  of  them  suspected  it  to  be  a  planet. 

The  inequalities  in  the  motions  of  Jupiter  and  Saturn,  which 
could  not  be  accounted  for  from  the  mutual  attractions  of  these 
planets,  led  astronomers  to  suppose  that  there  existed  another 
planet  beyond  the  orbit  of  Saturn,  by  whose  action  these  irregu- 
larities were  produced.  This  conjecture  was  confirmed  March 
13th,  1781,  when  Dr.  Herschel  discovered  the  motions  of  this 
body,  and  thus  proved  it  to  be  a  planet. 

Herschel  is  attended  by  six  moons  or  satellites,  which  revolve 
about  him  in  different  periods,  and  at  various  distances.  Four 
of  them  were  discovered  by  Dr.  Herschel,  and  two  by  his  sister, 
Miss  Caroline  Herschel.  It  is  possible  that  others  remain  yet 
to  be  discovered. 

Uranus'  mean  distance  from  the  sun  is  1828,000,000  of  miles ; 
more  than  twice  the  mean  distance  of  Saturn.  His  sidereal 


URANUS. 


281 


revolution  is  performed  in  84  years  and  1  month,  and  his  motion 
in  his  orbit  is  15,600  miles  an  hour.  He  is  supposed  to  have  a 
rotation  on  his  axis,  in  common  with  the  other  planets ;  but  as- 
tronomers have  not  yet  been  able  to  obtain  any  occular  proof  of 
such  a  motion. 

His  diameter  is  estimated  at  34,000  miles  ;  which  would  make 
his  volume  more  than  80  times  larger  than  the  earth's.  To  his 
inhabitants,  the  sun  appears  only  the  ^^  part  as  large  as  he 
does  to  us;  and  of  course  they  receive  from  him  only  that  small 
proportion  of  light  and  heat.  It  may  be  shown,  however,  that 
the  ^-J-g-  part  of  the  sun's  light  exceeds  the  illuminating  power 
of  800  full  moons.  This,  added  to  the  light  they  must  receive 
from  their  six  satellites,  will  render  their  days  and  nights  far 
from  cheerless. 

But  three  of  the  six  satellites  reported  by  Herschel,  have  been  observed 
by  those  who  have  followed  him. 

The  following  elements  are  for  the  epoch  1st  January,  1801,  reckon- 
ing from  the  mean  equinox : 

Mean  sid.  rev.  (84.02  years),  solar  days,        -*'''        -     30686.821  d. 
«     synod,  rev.  "         "  "       "       -        ,,.-...*  369.656" 

Mean  longitude,        -  -  -  -V'          177°  48'  23".0 

Mean  motion  in  orbit  in  a  mean  solar  day,  r..!'*?v<  -  42". 37 
Do.  per  annum,  -  -  V;*'>  '  "  4°  17' 45".  16 

Long,  of  perihelion,         -  -  -  -      167    31    16  .10 

Annual  mo.  of  apsides  east,   -  52  .50 

Inclination  of  orbit,          -  -         ;;;^m'        -          GO  46'  28  .44 

Long,  of  ascending  node,      -  -  -  72    59  35  .30 

Ann.  mo.  of  do.  eastward,  -  -  -  -        14  .16 

Eccentricity  of  orbit.     Semi  axis  maj.  unity,  -       0.04667938 

Greatest  equation  of  center.         -  -  -         5°  20'  57".  00 

Mean  app.  diam.  (35,000  miles  scarcely),  -  »***!'•«•  '  4  -°° 
True  diam.,  earth's  as  unity,  ,"•-,,...  -  . ,  :'*&%•  -  4.344 
Mass,  sun  as  unity,  -  -  ;.  »-.,'/,..•  J1  -0.0000558098 

Volume,  earth  as  unity,  -  -        '••  V.  ,'.        •-.-,,-         '  82 

Density,  sun's  as  unity,         -  -  -  -    1. 100 

Mean  distance  (1,800,000,000  miles),  earth's  as  unity,        19. 182390 


H<;rschel's 
Satellites. 

Sidereal  Revolution. 

Mean  Distance.  —  Semi- 
diameter  =  1  of  Planet. 

d.     h.     m.      s. 

I 

5     21     25     20 

13.120 

II 

8     16     57     47 

17.022 

III 

10     23     02     47 

19.845 

IV 

13     10     56     29 

22.752 

V 

38     01     48     00 

45.507 

VI 

107     16     39     56 

91.008 

Herschel's  periods,  of  two  of  these  satellites,  have  been  confirmed  by 
z2 


282  GEOGRAPHY  OF  THE  HEAVENS. 

his  son,  and  by  Dr.  Lament,  of  Munich ;  a  third  one  has  recently  been 
observed  by  Striive  of  Pulkova. 

From  an  extensive  series  of  measures,  a  flattening  at  the  poles,  and  a 
protuberance  at  the  equator  of  this  planet  has  been  detected,  demonstrat- 
ing a  rotation  upon  an  axis,  in  accordance  with  the  general  analogy  of 
the  planets. 


NEPTUNE  (FIRST  CALLED  LEVERRIER). 

THIS  is  the  most  remote  and  the  latest  discovered  of  all  the 
large  planets.  The  extsaordinary  circumstances  attending  its 
discovery,  have  given  to  this  object  an  interest  which  does  not 
attach  to  any  other  heavenly  body.  After  the  discovery  of  Ura- 
nus, in  1781,  efforts  were  made  to  reduce  its  motions  to  the 
known  laws  of  gravitation,  and  an  orbit  was  computed,  which, 
in  the  outset,  it  was  thought  would  represent  all  the  observed 
places  of  Uranus,  and  by  which  its  future  places  might  be  pre- 
dicted. In  a  short  time  this  orbit  was  found  to  be  at  fault :  the 
planet  was  gradually  leaving  it,  and  seemed  to  be  under  some 
unknown  influence,  which  involved  its  motions  in  mystery. 

After  the  lapse  of  many  years  from  the  discovery  of  Uranus, 
M.  Bouvard  resumed  the  investigation  of  its  orbit,  and  finally 
reached  the  conclusion  that  it  was  impossible  to  represent  at  the 
same  time,  by  any  orbit,  the  old  observed  places  of  the  planet 
and  the  new  ones,  or  those  taken  after  the  star  was  discovered 
to  be  a  planet.  He,  therefore,  rejected  the  ancient  observations 
as  more  likely  to  be  in  error,  and  adopting  the  recent  ones,  com- 
puted an  orbit  and  tables  for  Uranus,  which  it  was  hoped  might 
represent  the  future  places  of  the  planet. 

A  few  years  sufficed  to  show  that  this  orbit  and  these  tables 
were  defective.  The  computed  and  the  observed  places  of  the 
planet  did  not  agree,  and  the  difference  increased  from  year  to 
year,  until  it  attracted  the  attention  of  many  distinguished  as- 
tronomers. Some  were  disposed  to  attribute  these  irregularities 
to  a  relaxation  of  the  rigorous  laws  of  gravitation  in  those  re- 
mote regions  of  space ;  others  conceived  that  Uranus  might  be 
attended  by  some  large  satellite  which  was  swaying  it  from  its 
computed  orbit :  while  another  class  conceived  the  possible  ex- 
istence of  a  remote  undiscovered  planet,  under  whose  influence 
Uranus  was  made  to  break  away  from  its  computed  track. 

Under  these  circumstances,  a  young  astronomer,  M.  Leverrier, 
of  Paris,  as  early  as  1845,  at  the  request  of  M.  Arago,  under- 
took a  thorough  discussion  of  the  irregularities  of  Uranus,  with 
a  view  to  understand  their  cause;  and  incase  this  cause  should 
be  an  exterior  planet,  to  determine,  from  the  known  irregularities 


NEPTUNE.  283 

of  Uranus,  the  actual  place  of  the  unknown  disturbing  planet  at 
a  given  epoch. 

M.  Leverrier  commenced  by  determining,  with  all  accuracy, 
the  disturbing  influence  on  Uranus,  exerted  by  all  the  known 
bodies  of  the  solar  system,  and  more  especially  the  effects  of 
the  large  and  nearer  planets  Saturn  and  Jupiter.  His  memoir 
on  this  subject  was  presented  to  the  Academy  of  Sciences  of 
Paris,  on  the  10th  Nov.,  1845.  On  the  first  of  the  following 
June,  he  read  a  second  memoir  before  that  learned  body,  in  which 
he  demonstrates  that  the  irregularities  of  Uranus  cannot  be  ex- 
plained by  any  known  causes;  and  concludes  that  they  are  due 
to  an  unknown  planet  revolving  in  an  orbit  exterior  to  that  of 
Uranus,  and  as  far  from  Uranus  as  it  is  fro'm  the  sun  ;  and  whose 
place,  as  roughly  determined,  was,  on  the  1st  January,  1847,  in 
longitude  325°.  On  the  30th  August,  1846,  a  third  memoir  was 
read,  in  which  the  author  fixes  the  approximate  elements  of  his 
theoretical  planet,  its  mass,  and  its  position  for  the  1st  January, 
1847,  in  heliocentric  longitude  326°  32'.  On  the  5th  October, 
1846,  a  fourth  and  last  memoir  was  presented  to  the  Academy, 
in  which  M.  Leverrier  discusses  the  position  of  the  plane  of  the 
orbit  of  his  unknown  planet. 

These  wonderful  accounts  excited  the  greatest  interest  among 
astronomers,  yet  such  was  the  difficulty  of  the  problem,  that  few 
were  willing  to  believe  that  Leverrier's  computation  would  ever 
lead  to  the  discovery  of  his  imaginary  planet.  These  misgivings 
were  soon  dissipated.  On  the  1st  of  Sept.,  1846,  M.  Leverrier 
wrote  to  his  friend  Dr.  Galle,  of  Berlin,  requesting  him  to  direct 
his  telescope  to  the  place  in  the  heavens  which  his  calculations 
had  indicated  as  the  place  of  his  planet  at  that  date.  This  re- 
quest was  immediately  complied  with  ;  and  on  the  very  first 
evening  of  examination,  the  planet  was  actually  discovered 
within  less  than  one  degree  of  the  place  pointed  out  by  M. 
Leverrier ! 

In  the  mean  time,  the  publications  of  Leverrier  had  brought  to 
light  the  fact,  that  Mr.  Adams,  a  young  geometer  of  Cambridge, 
Eng.,  had  discussed  the  very  same  problem,  and  had  reached 
results  almost  exactly  coincident  with  those  of  Leverrier.  In- 
deed, Air.  Adams  had  obtained  his  results  some  months  previous 
to  M.  Leverrier,  but  having  failed  to  publish  them  to  the  world, 
thus  gave  to  his  distinguished  rival  tne  priority  and  right  of  dis- 
covery. The  wonderful  coincidence  of  the  results  obtained  by 
Leverrier  and  Adams,  seemed  to  fix  absolutely  the  fact  of  the 
discovery  of  the  planet  from  calculation.  The  news  of  its  dis- 
covery was  soon  spread  throughout  the  world,  and  excited  every 
where  the  deepest  interest.  The  intelligence  reached  Cincinnati 
on  the  28th  Oct.,  1846,  and  on  the  same  evening  the  planet  was 


284  GEOGRAPHY  OF  THE  HEAVENS. 

readily  detected  by  its  disk  with  the  great  refractor.  Its  diame- 
ter was  immediately  measured. 

The  new  planet  was  now  followed  with  great  interest  at  all 
the  principal  observatories  in  the  world,  with  the  view  of  dis- 
covering how  nearly  the  computed  elements  before  discovery 
would  agree  with  those  determined  from  actual  observation  after 
discovery.  As  the  planet  moved  extremely  slow,  this  would 
have  required  a  long  series  of  years,  but  for  a  most  important 
discovery  made  by  Mr.  S.  C.  Walker,  then  at  the  Washington 
observatory.  After  computing  an  orbit  of  the  new  planet  from 
the  best  data  then  in  existence,  he  traced  it  backward  for  fifty 
or  sixty  years,  in  the  hope  of  finding  that  its  place  had  been 
fixed  long  since  by  some  astronomer  who  had  observed  it,  be- 
lieving it  to  be  a  fixed  star.  His  research  was  rewarded  with  a 
brilliant  discovery.  Two  places  of  the  planet  were  obtained 
from  the  catalogue  of  Lalande,  as  far  back  as  1795,  which,  com- 
bined with  recent  places,  gave  sufficient  data  to  determine  with 
comparative  accuracy  the  elements  of  the  orbit  of  the  new  planet. 
A  difficulty  here  arose,  from  the  fact  that  a  great  discrepancy  ex- 
isted between  the  periodic  time  of  the  planet  and  that  computed 
by  M.  Leverrier.  His  computed  period  was  about  217  years, 
while  the  periodic  time  of  Neptune  is  about  164.  This  discre- 
pancy has  induced  some  astronomers  to  assert  that  the  discovery 
of  the  planet,  after  all,  was  accidental.  This  Leverrier  denies  ; 
and  here,  for  the  present,  the  matter  rests. 

Prof.  Pierce  of  Cambridge,  after  an  elaborate  research,  finds 
that  all  the  irregularities  of  Uranus  are  most  perfectly  accounted 
for  by  the  influence  of  the  new  planet;  so  that  in  case  this  re- 
sult may  be  relied  on,  this  great  problem  is  now  absolutely 
exhausted. 

The  following  are  the  elements  computed,  before  discovery, 
by  M.  Leverrier : 

Periodic  time,  years,          -            -        »ij«:!f   *r-*1  •  217.387 

Mean  distance,  earth  as  unity,             -            -  36.1539 

Mean  longitude,  1st  Jan.,  1847,      ...  318°  47'  4" 

Longitude  of  perihelion,          -        •,«-           -  284    45    8 

Mean  anomaly,    -            -         V-            -         •*  34     0156 

Equation  of  center,     -             -             -             -  7     44  49 

Heliocentric  longitude,  1st  Jan.,  1847,        -          •  *  r  32632 

Radius  vector,  earth's  unity,                -            -  33  06 

Mass,  j^j  of  the  sun's  mass. 
Adams'  elements,  computed  before  discovery : 

Mean  longitude,  Oct.  6th,  1846,         -         "X;         -  323°  02' 

Longitude  of  perihelion,              ...  299     1 1 
Eccentricity,              -        ^*  v         -          -.  v  ~, '«>'.'"      0.120615 

Mass,  sun's  as  unity,                   -             ,            •  0.00018000 


NEPTUNE.  285 

The  elements  obtained  since  the  discovery  of  the  planet  by 
Mr.  Walker,  and  by  using  the  place  of  the  planet  observed  by 
Lalande,  1795,  are  as  follows.  These  will  be  gradually  im- 
proved as  observations  are  multiplied. 

Long,  perihelion  point,  -  47°  12'  56".73  m.  eq.  1st.  Jan.,  1848. 
Long,  ascending  node,  -  -130  05  11  .04  m.  eq.  1st.  Jan.,  1848. 
Inclination,  -  -  -  1  46  58  .97 

Eccentricity,          ...         0.00871946 
Mean  daily  sid.  mot  on,     -        -        21  ".35448 

Long,  at  epoch,     -';':.        -  330<>  44'  4i".82 

Mr.  Lassell,  of  Liverpool,  discovered  a  satellite  to  Neptune, 
on  which  a  sufficient  number  of  observations  have  been  made  to 
determine,  with  considerable  accuracy,  the  mass  of  the  planet. 
This  has  been  computed  by  Prof.  Pierce,  of  Cambridge,  and  is 
found  to  differ  considerably  from  that  obtained  by  Leverrier  be- 
fore the  discovery.  From  observations  on  Lassell's  satellite  by 
Mr.  Bond,  of  Cambridge,  the  mass  of  Neptune  is  determined  to 
be  of  the  sun's  mass. 


With  this  mass  Prof.  Pierce  accounts  for  all  the  irregularities 
of  Uranus,  and  closes,  at  least  for  the  present,  the  investigation. 


COMETS. 

COMETS,  whether  viewed  as  ephemeral  meteors,  or  as  substan- 
tial bodies,  forming  a  part  of  the  solar  system,  are  objects  of  no 
ordinary  interest. 

When,  with  uninstructed  gaze,  we  look  upwards  to  the  clear 
sky  of  evening,  and  behold,  among  the  multitudes  of  heavenly 
bodies,  one,  blazing  with  its  long  train  of  light,  and  rushing  on- 
ward toward  the  center  of  our  system,  we  insensibly  shrink 
back  as  if  in  the  presence  of  a  supernatural  being. 

But  when,  with  the  eye  of  astronomy,  we  follow  it  through 
tts  perihelion,  and  trace  it  far  off,  beyond  the  utmost  verge  of 
the  solar  system,  till  it  is  lost  in  the  infinity  of  space,  not  to  re- 
turn for  centuries,  we  are  deeply  impressed  with  a  sense  of  that 
power  which  could  create  and  set  in  motion  such  bodies. 

Comets  are  distinguished  from  the  other  heavenly  bodies,  by 
their  appearance  and  motion.  The  appearance  of  the  planets  is 
globular,  and  their  motion  around  the  sun  is  nearly  in  the  same 
plane,  and  from  west  to  east;  but  the  comets  have  a  variety  of 
forms,  and  their  orbits  are  not  confined  to  any  particular  part  of 
the  heavens ;  nor  do  they  observe  any  one  general  direction. 


286  GEOGRAPHY   OF  THE  HEAVENS. 

The  orbits  of  the  planets  approach  nearly  to  circles,  while 
those  of  the  comets  are  very  elongated  elipses.  A  wire  hoop, 
for  example,  will  represent  the  orbit  of  a  planet.  If  two  oppo- 
site sides  of  the  same  hoop  be  extended,  so  that  it  shall  be  long 
and  narrow,  it  will  then  represent  the  orbit  of  a  comet.  The 
sun  is  always  in  one  of  the  foci  of  the  comet's  orbit. 

There  is,  however,  a  practical  difficulty  of  a  peculiar  nature  which  em- 
barrasses the  solution  of  the  question  as  to  the  form  of  the  cometary  or- 
bits. It  so  happens  that  the  only  part  of  the  course  of  a  comet  which 
can  ever  be  visible,  is  a  portion  throughout  which  the  ellipse,  the  para- 
bola and  hyperbola,  so  closely  resemble  each  other,  that  no  observations 
can  be  obtained  with  sufficient  accuracy  to  enable  us  to  distinguish  them. 
In  fact,  the  observed  path  of  any  comet,  while  visible,  may  belong  either 
to  an  ellipse,  parabola,  or  hyperbola. 

That  part  which  is  usually  brighter,  or  more  opake  than  the 
other  portions  of  the  comet,  is  called  the  nucleus.  This  is  sur- 
rounded by  an  envelop,  which  has  a  cloudy,  or  hairy  appearance. 
These  two  parts  constitute  the  body,  and.  in  many  instances, 
the  whole  of  the  comet. 

Most  of  them,  however,  are  attended  by  a  long  train,  called 
the  tail;  though  some  are  without  this  appendage,  and  as  seen 
by  the  naked  eye,  are  not  easily  distinguished  from  the  planets. 
Others,  again,  have  no  apparent  nucleus,  and  seem  to  be  only 
globular  masses  of  vapor. 

Nothing  is  known  with  certainty  of  the  composition  of  these 
bodies.  The  envelop  appears  to  be  nothing  more  than  vapor, 
becoming  more  luminous  and  transparent  when  approaching  the 
sun.  As  the  comets  pass  between  us  and  the  fixed  stars,  their 
envelops  and  tails  are  so  thin,  that  stars  of  very  small  magni- 
tudes may  be  seen  through  them.  Some  comets,  having  no  nu- 
cleus, are  transparent  throughout  their  whole  extent. 

The  nucleus  of  a  comet  sometimes  appears  opake,  and  it 
then  resembles  a  planet.  Astronomers,  however,  are  not  agreed 
upon  this  point.  Some  affirm  that  the  nucleus  is  always  trans- 
parent, and  that  comets  are  in  fact  nothing  but  a  mass  of  vapor, 
or  less  condensed  at  the  center.  By  others,  it  is  maintained  that 
the  nucleus  is  sometimes  solid  and  opake.  It  seems  probable, 
however,  that  there  are  three  classes  of  comets,  viz.:  1st.  Those 
which  have  no  nucleus,  being  transparent  throughout  their  whole 
extent;  2d.  Those  which  have  a  transparent  nucleus;  and,  3d. 
Those  having  a  nucleus  which  is  solid  and  opake. 

A  comet,  when  at  a  distance  from  the  sun,  viewed  through  a 
good  telescope,  has  the  appearance  of  a  dense  vapor  surrounding 
the  nucleus,  and  sometimes  flowing  far  into  the  regions  of  space. 
As  it  approaches  the  sun,  its  light  becomes  more  brilliant,  till  it 
reaches  its  perihelion,  when  its  light  is  more  dazzling  than  that 


COMETS.  287 

of  any  other  celestial  body,  the  sun  excepted.  In  this  part  of 
its  orbit  are  seen  to  the  best  advantage  the  phenomena  of  this 
wonderful  body,  which  has,  from  remote  antiquity,  been  the 
specter  of  alarm  and  terror. 

The  luminous  train  of  a  comet  us\iz\\y  follows  it,  as  it  ap- 
proaches the  sun,  and  goes  before  it,  when  the  comet  recedes  from 
the  sun ;  sometimes  the  tail  is  considerably  curved  towards  the 
region  to  which  the  comet  is  tending,  and  in  some  instances  it 
has  been  observed  to  form  a  right  angle  with  a  line  drawn  from 
the  sun  through  the  center  of  the  comet.  The  tail  of  the  comet 
of  1744,  formed  nearly  a  quarter  of  a  circle;  that  of  1689,  was 
curved  like  a  Turkish  sabre.  Sometimes  the  same  comet  has 
several  tails.  That  of  1744  had,  at  one  time,  no  less  than  six, 
which  appeared  and  disappeared  in  a  few  days.  The  comet  of 
1823  had,  for  several  days,  two  tails  ;  one  extending  toward  the 
sun,  and  the  other  in  the  opposite  direction. 

Comets,  in  passing  among  and  near  the  planets,  are  materially 
drawn  aside  from  their  courses,  and  in  some  cases  have  their 
orbits  entirely  changed.  This  is  remarkably  true  in  regard  to 
Jupiter,  which  seems  by  some  strange  fatality  to  be  constantly 
in  their  way,  and  to  serve  as  a  perpetual  stumbling  block  to 
them. 

"  The  remarkable  comet  of  1770,  which  was  found  by  Lexell  to  re- 
volve in  a  moderate  ellipse,  in  a  period  of  about  five  years,  actually  got 
entangled  among  the  satellites  of  Jupiter,  and  thrown  out  of  its  orbit  by 
the  attractions  of  that  planet,"  and  has  not  been  heard  of  since. — Her- 
schel,  p.  310.  By  this  extraordinary  rencounter,  the  motions  of  Jupiter's 
satellites  suffered  not  the  least  perceptible  derangement; — a  sufficient 
proof  of  the  aeriform  nature  of  the  comet's  mass. 

It  is  clear  from  observation,  that  comets  contain  very  little 
matter;  for  they  produce  little  or  no  effect  on  the  motion  of  the 
planets  when  passing  near  those  bodies.  It  is  said  that  a  comet, 
in  1454,  eclipsed  the  moon ;  so  that  it  must  have  been  very  near 
the  earth ;  yet  no  sensible  effect  was  observed  to  be  produced  by 
this  cause  upon  the  motion  of  the  earth  or  the  moon. 

The  observations  of  philosophers  upon  comets,  have  as  yet 
detected  nothing  of 'their  nature.  Tycho  Brahe  and  Appian 
supposed  their  tails  to  be  produced  by  the  rays  of  the  sun,  trans- 
mitted through  the  nucleus,  which  they  supposed  to  be  transpa- 
rent, and  to  operate  as  a  lens.  Kepler  thought  they  were  occa- 
sioned by  the  atmosphere  of  the  comet,  driven  off  by  the  impulse 
of  the  sun's  rays.  This  opinion,  with  some  modification,  was 
also  maintained  by  Euler.  Sir  Isaac  Newton  conjectured  that 
they  were  a  thin  vapor,  rising  from  the  heated  nucleus,  as  smoke 
ascends  from  the  earth  ;  while  Dr.  Hamilton  supposed  them  to 
be  streams  of  electricity. 


288  GEOGRAPHY  OF  THE  HEAVENS. 

"  That  the  luminous  part  of  a  comet,"  says  Sir  John  Herschel,  "  is 
something  in  the  nature  of  a  smoke,  fog,  or  cloud,  suspended  in  a  trans- 
parent atmosphere,  is  evident  from  a  fact  which  has  been  often  noticed, 
viz. :  that  the  portion  of  the  tail  where  it  comes  up  to,  and  surrounds  the 
head,  is  yet  separated  from  it  by  an  interval  less  luminous ;  as  we  often 
see  one  layer  of  clouds  laid  over  another  with  a  considerable  clear  space 
between  them."  And  again — "  It  follows  that  these  can  only  be  regarded 
as  great  masses  of  thin  vapor,  susceptible  of  being  penetrated  through 
their  whole  substance  by  the  sunbeams." 

Comets  have  always  been  considered  by  the  ignorant  and  su- 
perstitious, as  the  harbingers  of  war,  pestilence,  and  famine. 
Nor  has  this  opinion  been,  even  to  this  day,  confined  to  the  un- 
learned. It  was  once  universal.  And  when  we  examine  the 
dimensions  and  appearances  of  some  of  these  bodies,  we  cease 
to  wonder  that  they  produced  universal  alarm. 

According  to  the  testimony  of  the  early  writers,  a  comet, 
which  could  be  seen  in  daylight  with  the  naked  eye,  made  its 
appearance  43  years  before  the  birth  of  our  Saviour.  This  date 
was  just  after  the  death  of  Caesar,  and  by  the  Romans,  the  comet 
was  believed  to  be  his  metamorphosed  soul,  armed  with  fire  and 
vengeance.  This  comet  is  again  mentioned  as  appearing  in  1 106, 
and  then  resembling  the  sun  in  brightness,  being  of  a  great  size, 
and  having  an  immense  tail. 

In  the  year  1402,  a  comet  was  seen,  so  brilliant  as  to  be  dis- 
cerned at  noon-day. 

In  1456,  a  large  comet  made  its  appearance.  It  spread  a 
wider  terror  than  was  ever  known  before.  The  belief  was  very 
general,  among  all  classes,  that  the  comet  would  destroy  the 
earth,  and  that  the  Day  of  Judgment  was  at  hand  ! 

This  comet  appeared  again  in  the  years  1531,  1607,  1682,  1758,  and 
1835.  It  passed  its  perihelion  in  November,  1835,  and  will  every  75£ 
years  thereafter. 

At  the  time  of  the  appearance  of  this  comet,  the  Turks  exten- 
ded their  victorious  arms  across  the  Hellespont,  and  seemed  des- 
tined to  overrun  all  Europe.  This  added  not  a  little  to  the  gen- 
eral gloom.  Under  all  these  impressions,  the  people  seemed 
totally  regardless  of  the  present,  and  anxidlis  only  for  the  future. 
The  Romish  Church  held,  at  this  time,  unbounded  sway  over 
the  lives,  and  fortunes,  and  consciences  of  men.  To  prepare 
the  world  for  its  expected  doom,  Pope  Calixtus  III  ordered  the 
Ave  Maria  to  be  repeated  three  times  a  day,  instead  of  two. 
He  ordered  the  church  bells  to  be  rung  at  noon,  which  was  the 
origin  of  that  practice,  so  universal  in  Christian  churches.  To 
the  Ave  Maria,  the  prayer  was  added — "Lord,  save  us  from  the 
Devil,  the  Turk,  and  the  comet : "  and  once  each  day,  these 
three  obnoxious  personages  suffered  a  regular  excommunicaton. 


COMETS  289 

The  pope  and  clergy,  exhibiting  such  fear,  it  is  not  a  matter 
of  wonder  thvit  it  became  the  ruling  passion  of  the  multitude. 
The  churches  and  convents  were  crowded  for  confession  of 
sins ;  and  treasures  uncounted  were  poured  into  the  Apostolic 
chamber. 

The  comet,  after  suffering  some  months  of  daily  cursing,  and 
excommunication,  began  to  show  signs  of  retreat,  and  soon 
disappeared  from  those  eyes  in  which  it  found  no  favor. 
Joy  and  tranquillity  soon  returned  to  the  faithful  subjects  of  the 
pope,  but  not  so  their  money  and  lands.  The  people,  however, 
became  satisfied  that  their  lives,  and  the  safety  of  the  world,  had 
been  cheaply  purchased.  The  pope,  who  had  achieved  so 
signal  a  victory  over  the  monster  of  the  sky,  had  checked  the 
progress  of  the  Turk,  and  kept  for  the  present,  his  Satannic 
majesty  at  a  safe  distance;  while  the  church  of  Rome,  retaining 
her  unbounded  wealth,  was  enabled  to  continue  that  influence 
over  her  followers  which  she  retains,  in  part,  to  this  day. 

The  comet  of  1680  would  have  been  still  more  alarming  than 
that  of  1456,  had  not  science  robbed  it  of  its  terrors,  and  history 
pointed  to  the  signal  failure  of  its  predecessor.  This  comet 
was  of  the  largest  size,  and  had  a  tail  whose  enormous  length 
was  more  than  ninety-six  millions  of  miles. 

At  its  greatest  distance,  it  is  13,000,000  of  miles  from  the 
sun  ;  and  at  its  nearest  approach,  only  574,000  miles  from  his 
center;  or  about  130,000  miles  from  his  surface.  In  that  part 
of  its  orbit  which  is  nearest  the  sun,  it  flies  with  the  amazing 
swiftness  of  1,000,000  miles  in  an  hour,  and  the  sun  as  seen 
from  it,  appears  27,000  times  larger  than  it  appears  to  us ; 
consequently,  it  is  then  exposed  to  a  heat  27,000  times  greater 
than  the  solar  heat  at  the  earth.  This  intensity  of  heat  exceeds, 
several  thousand  times,  that  of  red-hot  iron,  and  indeed  all  the 
degrees  of  heat  that  we  are  able  to  produce.  A  simple  mass 
of  vapor,  exposed  to  a  thousandth  part  of  such  a  heat,  would  be 
at  once  dissipated  in  space — a  pretty  strong  indication  that, 
however  volatile  are  the  elements  of  which  comets  are  composed, 
they  are,  nevertheless,  capable  of  enduring  an  inconceivable 
intensity  of  both  heat  and  cold. 

This  is  the  comet  which,  according  to  the  reveries  of  Dr. 
Whiston,  and  others,  deluged  the  world  in  time  of  Noah. 
Whiston  was  the  friend  and  successor  of  Newton :  but,  anxious 
to  know  more  than  is  revealed,  he  passed  the  bounds  of  sober 
philosophy,  and  presumed  not  only  to  fix  the  residence  of  the 
damned,  but  also  the  nature  of  their  punishment.  According  to 
his  theory,  a  comet  was  the  awful  prison-house  in  which,  as  it 
wheeled  from  the  remotest  regions  of  darkness  and  cold  into  the 
very  vicinity  of  the  sun,  hurrying  its  wretched  tenants  to  the 

2A 


290  GEOGRAPHY  OF  THE  HEAVENS. 

extremes  of  perishing  cold  and  devouring  fire,  the  Almighty 
was  to  dispense  the  severities  of  his  justice. 

Such  theories  may  he  ingenious,  but  they  have  no  hasis  of 
facts  to  rest  upon.  They  more  properly  belong  to  the  chimeras 
of  Astrology,  than  to  the  science  of  Astronomy. 

When  we  are  told  by  philosophers  of  great  caution  and  high 
reputation,  that  the  fiery  train  of  the  comet,  just  alluded  to, 
extended  from  the  horizon  to  the  zenith  ;  and  that  of  1774  had, 
at  one  time,  six  tails,  each  6,000.000  of  miles  long ;  and  that 
another,  which  appeared  soon  after,  had  one  40.000.000  of  miles 
long;  and  when  we  consider  also  the  inconceivable  velocity 
with  which  they  speed  their  flight  through  the  sola,r  systeui,  we 
may  cease  to  wonder  if,  in  the  darker  ages,  they  have  been  re- 
garded as  evil  omens. 

But  these  idle  phantasies  are  not  peculiar  to  any  age  or  coun- 
try. Even  in  our  own  times,  the  beautiful  comet  of  1811,  the 
most  splendid  one  of  modern  times,  was  generally  considered 
among  the  superstitious,  as  the  dread  harbinger  of  the  war  which 
.was  declared  in  the  following  spring.  It  is  well  known  that  an 
indefinite  apprehension  of  a  more  dreadful  catastrophe  lately 
pervaded  both  continents,  in  anticipation  of  Biela's  comet 
of  1832. 

The  nucleus  of  the  comet  of  1811,  according  to  observations 
made  near  Boston,  was  2,617  miles  in  diameter,  corresponding 
nearly  to  the  size  of  the  moon.  The  brilliancy  with  which  it 
shone,  was  equal  to  one-tenth  of  that  of  the  moon.  The  envelop, 
or  aeriform  covering,  surrounding  the  nucleus,  was  24,000 
miles  thick,  about  five  hundred  times  as  thick  as  the  atmosphere 
which  encircles  the  earth  ;  making  the  diameter  of  the  comet, 
including  its  envelop,  50,617  miles.  It  had  a  very  luminous 
tail,  whose  greatest  length  was  one  hundred  millions  of  miles. 

This  comet  moved,  in  its  perihelion,  with  an  almost  inconceivable  ve- 
locity— fifteen  hundred  times  greater  than  that  of  a  ball  bursting  from  the 
mouth  of  a  cannon.  According  to  Regiomontanus,  the  comet  of  1472 
moved  over  an  arc  of  120°  in  one  day.  Brydone  observed  a  comet  at 
Palermo  in  1770,  which  passed  through  50°  of  a  great  circle  in  the  heav- 
ens, in  24  hours.  Another  comet,  which  appeared  in  1 759,  passed  over 
41°  in  the  same  time.  The  conjecture  of  Dr.  Halley,  therefore,  seems 
highly  probable,  that  if  a  body  of  such  a  size,  having  any  considerable 
density,  and  moving  with  such  a  velocity,  were  to  strike  our  earth,  it 
would  instantly  reduce  it  to  chaos,  mingling  its  elements  in  ruin. 

The  transient  effect  of  a  comet  passing  near  the  earth,  could  scarcely 
amount  to  any  great  convulsion,  says  Dr.  B  rewster :  but  if  the  earth  were 
actually  to  receive  a  shock 'from  one  of  these  bodies,  the  consequences 
would  be  awful.  A  new  direction  would  be  given  to  its  rotary  motion,  and 
U  would  revolve  around  a  new  axis.  The  seas,  foisaking  their  beds, 
would  be  hurried,  by  their  centrifugal  force,  to  the  new  equitorial  regions : 


COMETS.  291 

islands  and  continents,  the  abodes  of  men  and  animals,  would  be  covered 
by  the  universal  rush  of  the  waters  to  the  new  equator,  and  every  vestige 
of  human  industry  and  genius  would  be  at  once  destroyed. 

The  chances  against  such  an  event,  however,  are  so  very 
numerous,  that  there  is  no  reason  to  dread  its  occurrence.  The 
French  government,  not  long  since,  called  the  attention  of  some 
of  her  ablest  mathematicians  and  astronomers  to  the  solution  of 
this  problem;  that  is,  to  determine,  upon  mathematical  principles, 
how  many  chances  of  collision  the  earth  was  exposed  to.  After  a 
"nature  examination,  they  reported, — "  We  have  found  that,  of 
281,000,000  of  chances,  there  is  only  one  unfavorable, — there 
exists  but  one  which  can  produce  a  collision  between  the  two 
bodies." 

"  Admitting,  then,"  say  they,  "  for  a  moment,  that  the  comets  which 
may  strike  the  earth  with  their  nucleii,  would  annihilate  the  whole 
human  race  ;  the  dagger  of  death  to  each  individual,  resulting  from  the 
appearance  of  an  unknown  comet,  would  be  exactly  equal  to  the  risk  he 
would  run,  if  in  an  urn  there  was  only  one  single  white  ball  among  a 
total  number  of  28 1 ,000,000  balls,  and  that  his"  condemnation  to  death 
would  be  the  inevitable  consequence  of  the  white  ball  being  produced  at 
the  first  drawing." 

We  have  before  stated  that  comets,  unlike  the  planets, 
observe  no  one  direction  in  their  orbits,  but  approach  to  and 
recede  from  their  great  center  of  attraction,  in  every  possible 
direction.  Nothing  can  be  more  sublime,  or  better  calculated  to 
fill  the  mind  with  profound  astonishment,  than  to  contemplate 
the  revolution  of  comets,  while  in  that  part  of  their  orbits 
which  comes  within  the  sphere  of  the  telescope.  Some  seem  to 
come  up  from  the  immeasurable  depths  below  the  ecliptic,  and, 
having  doubled  the  heavens'  mighty  cape,  again  plunge  down- 
ward with  their  fiery  trains, 

'••;'.-      .'•' 

"  On  the  long  travel  of  a  thousand  years." 

Others  appear  to  come  down  from  the  zenith  of  the  universe 
to  double  their  perihelion  about  the  sun,  and  then  reascend  far 
above  all  human  vision. 

Others  are  dashing  through  the  solar  system  in  all  possible 
directions,  and  apparently  without  any  undisturbed  or  un- 
disturbing  path  prescribed  by  Him  who  guides  and  sustains 
them  all. 

Until  within  a  few  years,  it  was  universally  believed  that 
the  periods  of  their  revolutions  must  necessarily  be  of  prodigious 
length;  but  within  a  few  years,  two  comets  have  been  discov- 
ered, whose  revolutions  are  performed,  comparatively,  within 
our  own  neighborhood.  To  distinguish  them  from  the  more 
remote,  they  are  denominated  the  comets  of  a  short  period.  The 
first  was  discovered  in  the  constellation  Aquarius,  by  two  French 


292  GEOGRAPHY  OF  THE  HEAVENS. 

astronomers,  in  the  year  1786.  The  same  comet  was  again 
observed  by  Miss  Caroline  Hersehel.  in  the  constellation  Cyg- 
nus,  in  1795,  and  again  in  1805.  In  1818,  Professor  Encke 
determined  the  dimensions  of  its  orbit,*  and  the  period  of  its 
sidereal  revolution;  for  which  reason  it  has  been  called  " Encke?s 
Comet." 

This  comet  performs  its  revolution  around  the  sun  in  about  3 
years  and  4  months,  in  an  elliptical  orbit  which  lies  wholly 
within  the  orbit  of  Jupiter.  Its  mean  distance  from  the  sun  is 
212, 000,000  of  miles;  the  eccentricity  of  its  orbit  is  179,000,000 
of  miles;  consequently,  it  is  358,000,000  of  miles  nearer  the 
sun  in  its  perihelion,  than  it  is  in  its  aphelion.  It  was  visible 
throughout  the  United  States  in  1825,  when  it  presented  a  fine 
appearance.  It  was  also  observed  at  its  next  return  in  1828; 
but  its  last  return  to  its  perihelion,  on  the  6th  of  May,  1832, 
was  invisible  in  the  United  States,  on  account  of  its  great 
southern  declination. 

The  second  "  Comet  of  a  short  period,"  was  observed  in  1772; 
and  was  seen  again  in  1805.  It  was  not  until  its  re-appearance 
in  1826,  that  astronomers  were  able  to  determine  the  elements 
of  its  orbit,  and  the  exact  period  of  its  revolution.  This  was 
successfully  accomplished  by  M.  Biela,  of  Josephstadt;  hence  it 
is  called  Stela's  Comet.  According  to  observations  made  upon 
it  in  1805,  by  the  celebrated  Dr.  Olbers,  its  diameter,  including 
its  envelop,  is  42,280  miles.  It  is  a  curious  fact,  that  the  path 
of  Biela's  comet  passes  very  near  to  tha,t  of  the  earth  ;  so  near, 
that  at  the  moment  the  center  of  the  comet  is  at  the  point  near- 
est to  the  earth's  path,  the  matter  of  the  comet  extends  beyond 
that  path,  and  includes  a  portion  within  it.  Thus,  if  the  earth 
were  at  that  point  of  its  orbit  which  is  nearest  to  the  path  of  the 
comet,  at  the  same  moment  that  the  comet  should  be  at  that 
point  of  its  orbit  which  is  nearest  to  the  path  of  the  earth,  the 
earth  would  be  enveloped  in  the  nebulous  atmosphere  of  the 
comet. 

With  respect  to  the  effect  which  might  be  produced  upon  our 
atmosphere  by  such  a  circumstance,  it  is  impossible  to  offer  any 
thing  but  the  most  vague  conjecture.  Sir  John  Hersehel  was 
able  to  distinguish  stars  as  minute  as  the  16th  or  17th  magnitude 
through  the  body  of  the  comet !  Hence  it  seems  reasonable  to 
infer,  that  the  nebulous  matter  of  which  it  is  composed,  must  be 
infinitely  more  attenuated  than  our  atmosphere;  so  that  for 
every  particle  of  cometary  matter  which  we  should  inhale,  we 
should  inspire  millions  of  particles  of  atmospheric  air. 

This  is  the  comet  which  was  to  come  into  collision  with  the 
earth,  and  to  blot  it  out  from  the  solar  system.  In  returning  to 
its  perihelion,  November  26th,  1832,  it  was  computed  that  it 
would  cross  the  earth's  orbit  at  a  distance  of  only  18,500  miles. 


COMETS.  293 

It  is  evident  that  if  the  earth  had  been  in  that  part  of  her  orbit 
at  the  same  time  with  the  comet,  our  atmosphere  would  have 
mingled  with  the  atmosphere  of  the  comet,  and  the  two  bodies, 
perhaps,  have  come  in  contact.  But  the  comet  passed  the 
earth's  orbit  on  the  29th  of  October,  in  the  8th  degree  of  Sagit- 
tarius, and  the  earth  did  not  arrive  at  that  point  until  the  30th 
of  November,  which  was  32  days  afterwards. 

If  we  multiply  the  number  of  hours  in  32  days,  by  68,000 
(the  velocity  of  the  earth  per  hour),  we  shall  find  that  the  earth 
was  more  than  52,000,000  miles  behind  the  comet  when  it 
crossed  her  orbit.  Its  nearest  approach  to  the  earth,  at  any 
time,  was  about  51,000,000  of  miles;  its  nearest  approach  to 
the  sun,  was  about  83,000,000  of  miles.  Its  mean  distance 
from  the  sun,  or  half  the  longest  axis  of  its  orbit,  is  337,000,000 
of  miles.  Its  eccentricity  is  253,000,000  of  miles  ;  consequently, 
it  is  507,000,000  of  miles  nearer  the  sun  in  its  perihelion  than 
it  is  in  its  aphelion.  The  period  of  its  sidereal  revolution  is 
2,460  days,  or  about  6f  years. 

Up  to  the  beginning  of  the  17th  century,  no  correct  notions 
had  been  entertained  in  respect  to  the  paths  of  comets.  Kepler's 
first  conjecture  was,  that  they  moved  in  straight  lines;  but  as 
that  did  not  agree  with  observation,  he  next  concluded  that  they 
were  parabolic  curves,  having  the  sun  near  the  vertex,  and  run- 
ning indefinitely  into  the  regions  of  space  at  both  extremities, 
'['here  was  nothing  in  the  observations  of  the  earlier  astronomers 
to  fix  their  identity,  or  to  lead  him  to  suspect  that  any  one  of 
them  had  ever  been  seen  before;  much  less  that  they  formed  a 
part  of  the  solar  system,  revolving  about  the  sun  in  elliptical 
orbits  that  returned  into  themselves. 

This  grand  discovery  was  reserved  for  one  of  the  most  indus- 
trious and  sagacious  astronomers  that  ever  lived — this  was  Dr. 
Halley,  the  contemporary  and  friend  of  Newton.  When  the 
comet  of  1682  made  its  appearance,  he  set  himself  about  observ- 
ing it  with  great  care,  and  found  there  was  a  wonderful  resem- 
blance between  it  and  three  other  comets  that  he  found  recorded, 
the  comets  of  1456,  of  1531,  and  1607.  The  times  of  their  ap- 
pearance had  been  nearly  at  equal  and  regular  intervals  ;  their 
perihelion  distances  were  nearly  the  same  ;  and  he  finally  proved 
them  to  be  one  and  the  same  comet,  performing  its  circuit  around 
the  sun  in  a  period  varying  a  little  from  76  years.  This  is 
therefore  called  Halley's  comet.  It  is  the  very  same  comet  that 
filled  the  eastern  world  with  so  much  consternation  in  1456,  and 
became  an  object  of  so  much  abhorrence  to  the  church  of  Rome. 

The  three  periodic  comets,  Encke's,  Biela's,  and  Halley's, 
have  presented,  in  their  recent  returns,  some  extraordinary  phe- 
nomena. The  periodic  time  of  Encke's  comet  appears  to  have 
been  regularly  diminishing  since  its  discovery.  The  distin- 


294  GEOGRAPHY  OF  THE  HEAVENS. 

guished  astronomer  whose  name  it  bears,  after  a  rigorous  exami- 
nation of  all  the  known  causes  which  can  produce  such  an  effect, 
finally  reached  the  conclusion  that  there  must  exist,  throughout 
the  planetary  regions,  a  rare  medium,  capable  of  resisting  the 
motion  of  the  light  and  gaseous  comets.  This  startling  doctrine 
has  been  received  with  considerable  favor  among  the  learned, 
although  it  involves  nothing  less  than  the  final  destruction  of 
the  entire  solar  system.  In  case  a  resisting  medium  exist,  no 
matter  how  small  its  effect  on  the  planets  and  comets  may  be, 
yet  since  the  stability  of  the  entire  system  is  guaranteed  only  on 
the  hypothesis  that  the  revolutions  of  the  planets  are  without 
resistance,  it  follows  that,  sooner  or  later,  the  same  effects  sup- 
posed to  be  exhibited  by  Encke's  comet,  will  be  shown  by 
every  revolving  planet  and  satellite,  and  each,  in  succession, 
will  terminate  its  career  by  falling  into  the  sun.  Recent  obser- 
vations by  Sir  John  Herschel,  on  the  physical  constitution  of 
Halley's  comet  during  its  return  in  1835,  have  revealed  some 
truths  which  may,  in  the  end,  account  for  the  retardation  of 
Encke's  comet,  without  resorting  to  the  hypothesis  of  a  resisting 
medium.  He  conceives  that  the  laws  of  gravitation  will  not 
account  for  certain  phenomena  presented  by  Halley's  comet, 
and  that  we  will  be  compelled  to  admit  the  existence  of  a  repul- 
sive force,  developed  under  certain  circumstances,  among  the 
particles  composing  the  tails  and  gaseous  portions  of  comets. 

During  its  late  return,  Biela's  cornet  exhibited  the  wonderful 
phenomenon  of  an  actual  separation  into  two  distinct  portions. 
When  first  discovered,  the  cornet  presented  its  ordinary  appear- 
ance, but  in  the  course  of  the  following  month,  it  was  found 
to  consist  of  two  distinct  parts,  each  possessing  all  the  charac- 
teristics of  a  comet.  These  fragments  continued  to  separate 
from  each  other,  while  they  pursued  their  orbitual  career  around 
the  sun.  This  phenomenon  Sir  John  Herschel  is  disposed  to 
attribute  to  the  same  causes  which  are  operating  to  diminish  the 
periodic  time  of  Encke's  comet,  and  which  produced  such  sud- 
den and  wonderful  changes  in  the  appearance  of  Halley's  comet, 
during  its  return  in  1835. 

The  next  appearance  of  Biela's  comet  will  be  looked  for  with 
great  interest.  At  this  time  (July,  1848),  astronomers  are  on 
the  look-out  for  Encke's  comet.  Our  knowledge  of  the  physical 
constitution  of  these  mysterious  objects,  is  extremely  limited. 

The  number  of  comets  which  have  been  observed  since  the  Christian 
era,  amounts  to  700.  Scarcely  a  year  has  .passed  without  the  observa- 
tion of  one  or  two.  And  since  multitudes  of  them  must  escape  observa- 
tion, by  reason  of  their  traversing  that  part  of  the  heavens  which  is  above 
the  horizon  in  the  day  time,  their  whole  number  is  probably  many  thou- 
sands. Comets  so  circumstanced,  can  only  become  visible  by  the  rare 


COMETS  295 


coincidence  of  a  total  eclipse  of  the  sun — a  coincidence  which  happened, 
as  related  by  Seneca,  60  years  before  Christ,  when  a  large  comet  was 
actually  observed  very  near  the  sun. 

But  M.  Arago  reasons  in  the  following  manner,  with  respect  to  the 
number  of  comets  : — The  number  of  ascertained  comets,  which,  at  their 
least  distances,  pass  within  the  orbit  of  Mercury,  is  thirty.  Assuming 
that  the  comets  are  uniformly  distributed  throughout  the  solar  system, 
there  will  be  1 1 7,649  times  as  many  comets  included  within  the  orbit  of 
Herschel,  as  there  are  within  the  orbit  of  Mercury.  But  as  there  are  30 
within  the  orbit  of  Mercury,  there  must  be  3,529,470  within  the  orbit  of 
Herschel ! 

Of  97  comets  whose  elements  have  been  calculated  by  astronomers, 
24  passed  between  the  sun  and  the  orbit  of  Mercury;  33  between  the 
orbits  of  Mercury  and  Venus ;  21  between  the  orbits  of  Venus  and  the 
Earth  ;  1 5  between  the  orbits  of  Ceres  and  Jupiter.  Forty-nine  of  these 
comets  move  from  east  to  west,  and  48  in  the  opposite  direction. 

The  total  number  of  distinct  comets,  whose  paths  during  the  visible 
part  of  their  course  had  been  ascertained,  up  to  the  year  1832,  was  one 
hundred  and  thirty-seven. 

What  regions  these  bodies  visit,  when  they  pass  beyond  the 
limits  of  our  view  ;  upon  what  errands  they  come,  when  they 
again  revisit  the  central  parts  of  our  system  ;  what  is  the  differ- 
ence between  their  physical  constitution  and  that  of  the  sun  and 
planets  ;  and  what  important  ends  they  are  destined  to  accom- 
plish, in  the  economy  of  the  universe,  are  inquiries  which  natu- 
rally arise  in  the  mind,  but  which  surpass  the  limited  powers 
of  the  human  understanding  at  present  to  determine. 


296  GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTER  VIII. 

THE   TRANSLATION    OF    THE    SUN    AND    SOLAR  SYSTEM 
THROUGH    SPACE. 

HAVING  closed  a  rapid  survey  of  the  individual  objects  consti- 
tuting the  solar  system,  we  proceed  to  the  examination  of  the 
wonderful  discovery  made  by  Sir  William  Herschel,  and  re- 
cently confirmed  by  the  Russian  astronomers,  that  the  sun, 
attended  by  all  his  planets,  satellites,  and  comets,  is  moving  swiftly 
through  space. 

It  will  be  remembered,  that  the  sun  must  be  reckoned  among 
the  fixed  stars  ;  and,  indeed,  is  one  of  the  many  millions  of  stars 
composing  the  Galaxy,  01  Milky  Way.  So  soon  as  the  fact 
was  ascertained  beyond  question,  that  among  the  fixed  stars 
many  were  found,  which  after  years  of  attentive  examination, 
actually  changed  their  relative  positions  in  the  heavens,  it  was 
not  unnatural  to  conjecture  these  changes  to  be  the  effect  of 
parallax,  produced  by  the  movement  of  the  sun  and  his  system 
of  planets,  in  some  direction  through  the  regions  of  space. 

It  will  be  readily  seen,  that  in  case  such  a  movement  of  the 
eun  exists,  and  should  be  appreciable  in  amount,  when  compared 
with  the  distance  of  the  stars,  its  effect  would  be  to  produce  an 
apparent  change  among  the  relative  places  of  the  stars,  in  con- 
sequence of  the  fact  that  the  spectator  every  year  views  them 
from  a  different  point  of  absolute  space. 

The  extension  of  the  law  of  gravitation  to  the  fixed  stars,  by 
the  discovery  of  binary  systems,  reduced  it  to  a  certainty  that 
the  stars  exerted  a  mutual  influence  over  each  other;  and  from 
this  general  attraction  which  each  exerted  over  every  other,  it 
was  impossible  for  the  sun  to  escape.  The  result  of  this  gene- 
ral attraction  would  be  motion  in  some  direction.  To  demon- 
strate the  truth  of  this  conjecture  —  to  determine  the  direction, 
angular  velocity,  and  actual  movement  of  the  sun  and  system, 
have  been  the  great  questions  for  solution  during  the  last  few 
years  of  astronomical  research. 

Sir  W.  Herschel  had  roughly  examined  this  subject;  and 
from  a  general  examination  of  the  proper  motion  of  the  fixed 
stars,  concluded  that  the  solar  system  was  moving  toward  the 
constellation  Hercules.  For  many  years,  this  theory  was  re- 
ceived with  comparatively  little  favor.  The  speculation  was  so 


TRANSLATION  OF  THE  SUN  THROUGH  SPACE.     297 

bold,  so  daring,  and  apparently  so  far  beyond  the  scope  of  accu- 
rate examination,  that  many  minds  were  indisposed  to  receive 
it.  Within  a  few  years,  however,  the  subject  has  been  taken 
up  by  M.  Argelander,  a  Russian  astronomer,  and  the  grand 
speculation  of  Herschel  has  become  a  matter  of  absolute  science. 

Argelander's  general  method  of  determining  the  direction  of 
the  solar  motion,  may  be  thus  explained,  in  its  general  outlines. 
He  commenced  by  fixing,  with  accuracy,  the  places  of  five  hun- 
dred stars,  in  all  the  visible  parts  of  the  heavens.  His  own 
determined  places  of  these  stars  were  then  compared  with  the 
places  of  the  same  stars  determined  by  preceding  astronomers. 
The  old  position  of  any  star,  joined  with  its  new  position,  would 
give  its  direction  of  apparent  motion,  and  the  distance  between 
the  two  places,  combined  with  the  interval  between  the  old  and 
new  observations,  would  fix  the  rate  of  movement  per  annum. 

The  five  hundred  selected  stars  were  then  grouped  into  three 
classes,  according  to  their  annual  rate  of  motion.  The  most 
swiftly-moving,  composing  the  first  class,  were  examined  sepa- 
rately in  this  way.  The  old  and  new  places  of  each  star  being 
joined,  the  line  thus  determined  in  position,  made  a  certain  angle 
with  the  meridian,  which  could  easily  be  determined.  All  these 
angles  were  computed  ;  and  by  an  examination  of  their  values, 
it  was  seen  that  their  general  direction  indicated,  that  in  case 
the  proper  motions  of  these  stars  were  occasioned  by  the  move- 
ment of  the  solar  system  through  space,  the  direction  of  that 
motion  must  be,  as  Herschel  had  said,  toward  the  constellation 
Hercules. 

A  point  in  this  constellation  was  now  selected,  as  the  one 
toward  which  the  sun  was  moving;  and,  on  this  hypothesis, 
the  directions  in  which  the  stars  already  examined  would  ap- 
pear to  move,  were  accurately  computed.  Now  in  case  these 
computed  directions  should  in  every  instance  coincide  with  the 
actual  observed  directions,  it  would  demonstrate  that  the  point 
had  been  well  chosen,  and  was  the  true  point  required  ;  while  a 
want  of  coincidence  would  show  that  another  trial  must  be 
made. 

Thus  did  Argelander  proceed,  with  incredible  pains,  to  select 
and  test  one  point  after  another,  until  he  obtained  one,  which, 
better  than  all  others,  harmonized  all  the  proper  motions  of  his 
five  hundred  stars;  and  this  was  the  point  towards  which,  it 
now  became  certain,  the  sun,  with  all  his  attendants,  was  urginsr 
his  flight. 

A  subsequent    investigation,  by  M.  Striive,   has  confirmed 
Argelander's  results  in  the  most  remarkable  manner.     Having 
accomplished  this  object,  M.  Striive  gave  his  attention  to  the 
determination  of  the  amount  of  angular  motion  of  the  solar  sys-  ' 
tern,  as  seen  from  the  mean  distance  of  the  stars  of  the  1st  mag- 


298  GEOGRAPHY  OF   TL ...  HEAVENS. 

nitude  ;  and  by  a  complex  and  elal urate  investigation,  finally 
ascertained,  that  in  each  year,  the  sun's  angular  motion  amounted 
to  three  hundred  and  thirty-five  thousandths  of  one  second  of 
arc,  or  this  would  be  the  angle  included  between  two  visual 
rays,  drawn  from  the  eye  of  a  spectator  removed  to  the  mean 
distance  of  stars  of  the  1st  magnitude,  to  the  two  places  occu- 
pied by  the  sun  at  the  beginning  and  close  of  the  same  year. 

Having  learned  the  value  of  this  distance  approximately,  we 
may  now  convert  this  angular  motion  into  linear  movement,  and 
we  reach  the  following  wonderful  proposition,  viz.  : — The  sun, 
attended  by  all  his  planets,  satellites,  and  comets,  is  sweeping 
through  space,  towards  the  star  ?r,  in  the  constellation  Hercules, 
at  the  rate  of  thirty-three  millions  three  hundred  and  fifty  thousand 
miles  in  every  year. 

Such  is  the  latest  determination,  with  reference  to  the  magni- 
ficent system  with  which  we  are  associated. 


LAW  OF  UNIVERSAL  GRAVITATJON. 

IT  is  said,  that  Sir  Isaac  Newton,  when  he  was  drawing  to  a 
close  the  demonstration  of  the  great  truth,  that  gravity  is  the 
cause  which  keeps  the  heavenly  bodies  in  their  orbits,  was  so 
much  agitated  with  the  magnitude  and  importance  of  the  dis- 
covery he  was  about  to  make,  that  he  was  unable  to  proceed, 
and  desired  a  friend  to  finish  what  the  intensity  of  his  feelings 
did  not  allow  him  to  do.  By  gravitation  is  meant,  that  univer- 
sal law  of  attraction,  by  which  every  particle  of  matter  in  the 
system  has  a  tendency  to  every  other  particle. 

This  attraction,  or  tendency  of  bodies  toward  each  other,  is 
in  proportion  to  the  quantity  of  matter  they  contain.  The  earth, 
being  immensely  large  in  comparison  with  all  other  substances 
in  its  vicinity,  destroys  the  effect  of  this  attraction  between 
smaller  bodies,  by  bringing  them  all  to  itself. 

The  attraction  of  gravitation  is  reciprocal.  All  bodies  not 
only  attract  other  bodies,  but  are  themselves  attracted,  and  both 
according  to  their  respective  quantities  of  matter.  The  sun,  the 
largest  body  in  our  system,  attracts  the  earth  and  all  the  other 
planets,  while  they  in  turn  attract  the  sun.  The  earth,  also, 
attracts  the  moon,  and  she  in  turn  attracts  the  earth.  A  ball, 
thrown  upward  from  the  earth,  is  brought  again  to  its  surface; 
the  earth's  attraction  not  only  counterbalancing  that  of  the  ball, 
but  also  producing  a  motion  of  the  ball  toward  itself. 

This  disposition,  or  tendency  toward   the  earth,  is  manifested 

•in  whatever  falls,  whether  it  be  a  pebble  from  the  hand,  or  an 

apple  from  a  tree,  or  an  avalanche  from  a  mountain.     All  terres- 


LAW  O1    GRAVITATION.  299 

trial  bodies,  not  excepting  the  waters  of  the  ocean,  gravitate 
toward  the  center  ;f  the  earth,  and  it  is  by  the  same  power  that 
animals  on  all  parts  of  the  globe  stand  with  their  feet  pointing 
to  its  center. 

The  power  of  terrestrial  gravitation  is  greatest  at  the  earth's 
surface,  whence  it  decreases  both  upward  and  downward  ;  but 
not  both  ways  in  the  same  proportion.  It  decreases  upward 
as  the  square  of  the  distance,  from  the  earth's  center  increases  ; 
so  that  at  a  distance  from  the  center  equal  to  twice  the  semi- 
diameter  of  the  earth,  the  gravitating  force  would  be  only  one 
fourth  of  what  it  is  at  the  surface.  But  below  the  surface,  it 
decreases  in  the  direct  rafio  of  the  distance  from  the  center ;  so 
that  at  a  distance  of  half  a  semi-diameter  from  the  center,  the 
gravitating  force  is  but  half  what  it  is  at  the  surface. 

Weight  and  gravity,  in  this  case,  are  synonymous  terms. 
We  say  a  piece  of  lead  weighs  a  pound,  or  16  ounces ;  but  if  by 
any  means  it  could  be  raised  4000  miles  above  the  surface  of 
the  earth,  which  is  about  the  distance  of , the  surface  from  the 
center,  and  consequently  equal  to  two  serni-diameters  of  the 
earth  above  its  center,  it  would  weigh  only  one  fourth  of  a  pound, 
or  four  ounces  ;  and  if  the  same  weight  could  be  raised  to  an 
elevation  of  12,000  miles  above  the  surface,  or  four  semi-diame- 
ters above  the  center  of  the  earth,  it  would  there  weigh  only  one 
sixteenth  of  a  pound,  or  one  ounce. 

The  same  body,  at  the  center  of  the  earth,  being  equally 
attracted  in  every  direction,  would  be  without  weight;  at  1000 
miles  from  the  center  it  would  weigh  one  fourth  of  a  pound  ;  at 
2000  miles,  one  half  of  a  pound;  at  3000  miles,  thr^e  fourths 
of  a  pound  ;  and  at  4000  miles,  or  at  the  surface,  one  pound. 

It  is  a  universal  law  of  attraction,  that  its  power  decreases,  as  the 
square  of  the  distance  increases.  The  converse  of  this  is  also  true,  viz. 
The  power  increases,  as  the  square  of  the  distance  decreases.  Giving 
to  this  law  the  form  of  a  practical  rule,  it  will  stand  thus : 

T/ie  gravity  of  bodies  above  the  surface  of  the  earth,  decreases  in  a 
duplicate  ratio  (or  as  the  squares  of  their  distances),  in  semi-diame- 
ters of  the  earth,  from  the  earth's  center.  That  is,  when  the  gravity  is 
increasing,  multiply  the  weight  by  the  square  of  the  distance ;  but  when 
the  gravity  is  decreasing,  divide  the  weight  by  the  square  of  the  distance. 

Suppose  a  body  weighs  40  pounds  at  2000  miles  above  the  earth's 
surface,  what  would  it  weigh  at  the  surface,  estimating  the  earth's  semi- 
diameter  at  4000  miles'!  From  the  center  to  the  .given  bight,  is  1^ 
semi- diameters:  the  square  of  l£,  or  1.5,  is  2.25,  which,  multiplied  into 
the  weight  (40),  gives  90  pounds,  the  answer. 

Suppose  a  body  which  weighs  256  pounds  upon  the  surface  of  the 
earth,  be  raised  to  the  distance  of  the  moon  (240,000  miles),  what  would 
be  its  weight  ]  Thus,  4000)240,000(60  semi-diameters,  the  square  of 
which  is  3600.  As  the  gravity,  in  this  case,  is  decreasing,  divide  the 


300  GEOGRAPHY   OF  THE   HEAVENS. 

weight  by  the  square  of  the  distance,  and  it  will  give  3600)256(1-1  fth 
of  a  pound,  or  1  ounce. 

2.  To  find  to  what  bight  a  given  weight  must  be  raised  to  lose  a 
certain  portion  of  its  weight. 

RILK. — Divide  the  weight  at  the  surf  nee,  by  the  required  weight, 
and  extract  the  square  root  of  the  quotient.  Ex.  A  boy  weighs  100 
pounds,  how  high  must  he  be  carried  to  weigh  but  4  pounds !  Thus, 
100  divided  by  4,  gives  25,  the  square  root  of  which  is  5  serai-diameters, 
or  20,000  miles  above  the  center. 

Bodies  of  equal  magnitude,  do  not  always  contain  equal 
quantities  of  matter;  a  ball  of  cork,  of  equal  bulk  with  one  of 
lead,  contains  less  matter,  because  it  is  more  porous.  The  sun, 
though  fourteen  hundred  thousand  times  larger  than  the  earth, 
being  much  less  dense,  contains  a  quantity  of  matter  only 
355,000  times  as  great,  and  hence  attracts  the  earth  with  a  force 
only  355,000  times  greater  than  that  with  which  the  earth 
attracts  the  sun. 

The  quantity  of  matter  in  the  sun,  is  780  times  greater  than 
that  of  all  the  planets  and  satellites  belonging  to  the  solar  sys- 
tem ;  consequently  their  whole  united  force  of  attraction  is  780 
times  less  upon  the  sun,  than  that  of  the  sun  upon  them. 

The  center  of  gravity  of  a  body,  is  that  point  in  which  its 
whole  weight  is  concentrated,  and  upon  which  it  would  rest,  if 
freely  suspended.  If  two  weights,  one  of  ten  pounds,  the  other 
of  one  pound,  be  connected  together  by  a  rod  eleven  feet  long, 
nicely  poised  on  a  center,  and  then  be  thrown  into  a  free  rotary 
motion,  the  heaviest  will  move  in  a  circle  with  a  radius  of  one 
foot,  and  the  lightest  will  describe  a  circle  with  a  radius  of  ten 
feet;  the  center  around  which  they  move  is  their  common  center 
of  gravity. 

Thus  the  sun  and  planets  move  around  an  imaginary  point  as 
a  center,  always  preserving  an  equilibrium. 

If  there  were  but  one  body  in  the  universe,  provided  it  were 
of  uniform  density,  the  center  of  it  would  be  the  center  of  gravity 
toward  which  all  the  surrounding  portions  would  uniformly 
tend,  and  they  would  thereby  balance  each  other.  Thus  the 
center  of  gravity,  and  the  body  itself,  would  forever  remain  at 
vest.  It  would  neither  move  up  nor  down  ;  there  being  no  other 
Dody  to  draw  it  in  any  direction.  In  this  case,  the  terms  up  and 
down  would  have  no  meaning,  except  as  applied  to  the  body 
'tself,  to  express  the  direction  of  the  surface  from  the  center. 

Were  the  earth  the  only  body  revolving  about  the  sun,  as  the 

un's  quantity  of  matter  is  355,000  times  as  great  as  that  of  the 

earth,  the  sun  would  revolve  in  a  circle  equal  only  to  the  three 

hundred  and  fifty-jive  thousandth  part  of  the  earth's  distance  from 

it :  but  as  the  planets  in  their  several  orbits  vary  their  positions, 


LAW  OF  GRAVITATION.  301 

the  center  of  gravity  is  not  always  at  the  same  distance  from 
the  sun. 

The  quantity  of  matter  in  the  sun  so  far  exceeds  that  of  all 
the  planets  together,  that  were  they  all  on  one  side  of  him,  he 
would  never  he  more  than  his  own  diameter  from  the  common 
center  of  gravity;  the  sun,  is,  therefore,  justly  considered  as  the 
center  of  the  system. 

The  quantity  of  matter  in  the  earth  being  about  80  times  as 
great  as  that  of  the  moon,  their  common  center  of  gravity  is  80 
times  nearer  the  former  than  the  latter,  which  is  about  3000 
miles  from  the  earth's  center. 

The  secondary  planets  are  governed  by  the  same  laws  as  their 
primaries,  and  both  together  move  around  a  common  center  of 
gravity. 

Every  system  in  the  universe  is  supposed  to  revolve,  in  like 
manner,  around  one  common  center. 


ATTRACTIVE   AND   PROJECTILE  FORCES. 

ALL  simple  motion  is  naturally  rectilinear;  that  is,  all  bodies 
put  in  motion  would  continue  to  go  forward  in  straight  lines,  as 
long  as  they  met  with  no  resistance  or  diverting  force. 

On  the  other  hand,  the  sun,  from  his  immense  size,  would,  by 
the  power  of  attraction,  draw  all  the  planets  to  him,  if  his  attrac- 
tive force  were  not  counterbalanced  by  the  primitive  impulse  of 
the  planetary  bodies  to  move  in  straight  lines. 

The  attractive  power  of  a  body  drawing  another  body  toward 
the  center,  is  denominated  centripetal  force ,•  and  the  tendency 
of  a  revolving  body  to  fly  from  the  center  in  a  tangent  line,  is 
called  the  projectile  or  centrifugal  force.  The  joint  action  of 
these  two  central  forces  gives  the  planets  a  circular  motion,  and 
retains  them  in  their  orbits  as  they  revolve,  the  primaries  about 
the  sun,  and  the  secondaries  about  their  primaries. 

The  degree  of  the  s-an's  attractive  power  at  each  particula? 
planet,  whatever  be  its  distance,  is  uniformly  equal  to  the  cen- 
trifugal force  of  the  planet.  The  nearer  any  planet  is  to  the 
sun,  the  more  strongly  is  it  attracted  by  him  ;  the  farther  any 
planet  is  from  the  sun,  the  less  is  it  attracted  by  him  ;  therefore, 
those  planets  which  are  the  nearer  to  the  sun  must  move  the 
faster  in  their  orbits,  in  order  thereby  to  acquire  centrifugal 
forces  equal  to  the  power  of  the  sun's  attraction ;  and  those 
which  .are  the  farther  from  the  sun  must  move  the  slower,  in 
order  that  they  may  not  have  too  great  a  degree  of  centrifugal 
force,  for  the  weaker  attraction  of  the  sun  at  4hose  distances. 
2B 


302  GEOGRAPHY  OF   THE  HEAVENS. 

The  discovery  of  these  great  truths,  by  Kepler  and  Newton, 
established  the  UNIVERSAL  LAW  OF  PLANETARY  MOTION  ;  which 
snay  be  stated  as  follows. 

1.  Every  planet  moves  in  its  orbit  with  a  velocity  varying 
every  instant,  in  consequence  of  two  forces;  one  tending  to  the 
center  of  the  sun,  and  the  other  in  the  direction  of  a  tangent  to 
its  orbit,  arising  from  the  primitive  jmpulse  given  at  the  time  it 
was  launched  into  space..    The  former  is  called  its  centripetal,  the 
latter,   its  centrifugal  force.     Should  the  centrifugal  force  cease, 
the  planet  would  fall  to  the  sun  by  its  gravity;  were  the  sun 
not  to  attract  it,  it  would  fly  off  from  its  orbit  in  a  straight  line. 

2.  By  the  time  a  planet  has  reached  its  aphelion,  or  that  point 
of  its  orbit  which  is  farthest  from  the  sun,  his  attraction  has 
overcome  its  velocity,  and  draws  it  toward  him   with  such  an 
accelerated  motion,  that  it  at  last  overcomes  the  sun's  attraction, 
and  shoots  past  him;  then  gradually  decreasing  in  velocity,  it 
arrives  at  the  perihelion,  when  the  sun's  attraction  again  prevails. 

3.  However  ponderous  or  light,  large  or  small,  near  or  remote, 
the  planets  may  be,  their  motion  is  always  such  that  imaginary 
lines  joining  their  centers  to  the  sun,  pass  over  equal  areas  in 
equal  times :  and  this  is  true  not  only  with  respect  to  the  areas 
described  every  hour  by  the  same  planet,  but  the  agreement  holds, 
with  rigid  exactness,  between  the  areas  described  in  the  same 
time,   by   all  the  planets  and  comets  belonging  to  the   solar 
system. 

From  the  foregoing  principles,  it  follows,  that  the  force  of  gravity,  and 
the  centrifugal  force,  are  mutual  opposing  powers — each  continually  act- 
ing against  the  other.  Thus,  the  weight  of  bodies,  on  the  eanh's  equa- 
tor, is  diminished  by  the  centrifugal  force  of  her  diurnal  rotation,  in  the 
proportion  of  one  pound  for  every  two  hundred  and  ninety  pounds  :  that 
is,  had  the  earth  no  motion  on  her  axis,  all  bodies  on  the  equator  would 
weigh  one  two  hundred  and  eighty-ninth  part  more  than  they  now  do. 

On  the  contrary,  if  her  diurnal  motion  were  accelerated,  the  centrifugal 
force  would  be  proportionally  increased,  and  the  weight  of  bodies  at  the 
equator  would  be,  in  the  same  ratio,  diminished.  Should  the  earth  revolve 
upon  its  axis,  with  a  velocity  which  would  make  the  day  but  eighty-four 
minutes  long,  instead  of  twenty-four  hours,  the  centrifugal  force  would 
counterbalance  that  of  gravity,  and  all  bodies  at  the  equator  would  then 
be  absolutely  destitute  of  weight ;  and  if  the  centrifugal  force  were  farther 
augmented,  (the  earth  revolving  in  less  time  than  eighty-four  minutes'), 
gravitation  would  be  completely  overpowered,  and  all  fluids  and  loose 
substances  near  the  equator  would  fly  off  from  the  surface. 

The  weight  of  bodies,  either  upon  the  earth,  or  on  any  other  planet  hav- 
ing a  motion  around  its  axis,  depends  jointly  upon  the  mass  of  the  planet^ 
and  its  diurnal  velocity.  A  body  weighing  one  pound  upon  the  equator 
of  the  earth,  would  weigh,  if  removed  to  the  equator  of-  the  sun,  27.91bs. 
Of  Mercury,  1.03  Ibs.  Of  Venus,  0.98  Ibs.  Of  the  moon,  »  Ib.  Of 
Mars,  i  Ib.  Of  Jupiter,  2.716  Ibs.  Of  Saturn,  1.01  Ibs. 


PRECESSION  OF   THE  EQUINOXES.  303 


CHAPTER   IX. 

PRECESSION,  NUTATION,  ABERRATION,  PARALLAX, 
REFRACTION. 

IN  attempting  to  fix  the  place  of  any  heavenly  body,  at  a  given 
epoch,  for  the  purpose  of  ascertaining  its  subsequent  movements, 
it  is  absolutely  indispensable  to  know  the  precise  changes  which 
are  affecting  the  points  or  lines  to  which  the  heavenly  body  is 
referred,  and  by  means  of  which  its  place  is  determined. 

The  longitude  and  right  ascension  are  both  reckoned  from  the 
same  point,  viz,  the  vernal  equinox,  and  in  case  this  point  is  not 
fixed,  then  to  know  with  accuracy  the  place  of  a  star  or  planet 
referred  to  the  vernal  equinox,  we  must  learn  the  precise  amount 
of  change  in  the  place  of  this  point  of  reference. 

If  the  sun  in  its  apparent  annual  motion  among  the  fixed  stars, 
passed  over  the  same  identical  track  every  year,  then  the  points 
in  which  his  orbit  cuts  the  celestial  equator  would  be  ever  in- 
variable. This,  however,  is  not  the  case.  The  sun's  path  among 
the  fixed  stars,  is  slowly  but  constantly  changing.  If  a  bright 
star  this  year  should  happen  to  occupy  the  exact  point  in  which 
the  sun's  path  crosses  the  equator  in  the  spring,  at  the  end  of 
one  year  the  sun  would  come  round  and  would  cross  the  equator 
so  as  to  leave  that  star  a  little  to  the  east. 

This  apparent  yearly  motion  of  the  sun  westward,  causes  it 
to  reach  the  equinox  or  to  come  to  the  equator  earlier  than  it 
otherwise  would  do,  and  in  this  way  brings  on  an  equality 
between  the  days  and  nights,  sooner  than  it  would  have  come 
had  the  sun's  apparent  orbit  been  fixed.  Because  the  sun  in 
this  way  comes  to  the  equinox  at  a  time  preceding  its  former 
arrival,  it  has  been  called  a  precession  of  the  equinoxes,  while 
in  reality  it  is  a  recession  or  receding  of  the  equinoctial  points 
along  the  equator.  We  shall  now  in  a  few  words  trace  this  ex- 
traordinary phenomenon  to  its  origin,  point  out  its  effects,  and 
present  its  exact  numerical  value. 

The  swift  rotation  of  the  earth  on  its  axis,  causes  a  protuber- 
ance or  elevation  around  its  equatorial  regions  as  we  have  already 
seen.  This  belt  of  matter  heaped  up  at  the  equator,  is  subjected 
to  the  attractive  energy  of  the  sun  and  moon,  and  by  their  com- 
bined action  exerted  on  this  belt  of  redundant  matter,  the  solid 
earth  is  made  to  reel  slightly  on  its  axis.  Now  the  plane  of  the 
earth's  equator  produced  cuts  from  the  heavens  the  equinoctial, 


304  GEOGRAPHY   OF   THE   HEAVENS. 

and  in  case  this  plane  be  in  any  way  deranged  or  moved,  it  will 
cease  to  cut  the  ecliptic  in  its  former  points.  It  will  be  seen 
readily  that  whatever  cause  operates  to  displace  the  earth's 
equator,  must  operate  to  change  the  position  of  the  equinoctial 
points. 

Again  :  as  the  earth's  axis  is  ever  perpendicular  to  the  earth's 
equator,  it  follows  that  every  change  in  the  position  of  the  equa- 
tor, involves  a  corresponding  change  in  the  position  of  the  earth's 
axis.  To  exhibit  this  to  the  eye,  take  a  wooden  wheel,  puss 
through  its  center  an  axis,  and  then  let  the  wheel  and  axis  float 
on  still  water.  If  the  wheel  be  one  half  sunk  below  the  surface 
of  the  water,  the  other  half  coming  up  above  the  surface,  then 
will  the  axis  cease  to  be  vertical,  and  will  become  inclined  to- 
ward the  immersed  portion  of  the  wheel's  rim.  Repeat  the  ex- 
periment at  any  point  of  the  rim,  and  it  will  be  found  that  every 
motion  of  the  wheel  involves  a  corresponding  motion  of  the  axis. 

The  wheel  represents  the  earth's  equator,  the  axis  that  of  the 
earth,  and  the  surface  of  the  still  water  the  plane  of  the  earth's 
orbit.  In  the  long  run,  the  effect  of  the  combined  action  of  the 
sun  and  moon,  on  the  equator  of  the  earth,  causes  it  to  cut  the 
ecliptic  in  two  opposite  points,  which  move  slowly  backward 
every  year,  and  accomplish  an  entire  revolution  in  about  26,000 
years.  As  this  motion  is  represented  exactly  by  the  earth's 
axis,  it  follows  that  in  the  same  period  the  pole  of  the  equator, 
or  north  pole  of  the  heavens,  will  revolve  around  the  pole  of  the 
ecliptic. 

The  exact  value  of  precession,  as  recently  determined  by  M. 
Striive,  is  50". 23449  ;  a  quantity  of  the  utmost  importance,  in 
the  nice  investigations  of  sidereal  astronomy. 

In  consequence  of  the  motion  of  the  north  pole  of  the  heavens, 
the  bright  star  Polaris,  now  near  the  pole,  will  ultimately  be 
left  far  behind,  and  at  the  expiration  of  about  12,000  years,  the 
brilliant  star  Vega,  in  the  Lyre,  will  become  the  polar  star. 

Nutation  is  a  subordinate  effect  of  the  same  general  causes 
producing  precession.  It  was  discovered  by  Bradley,  and  is 
due  to  the  joint  influence  of  the  sun  and  moon  on  the  protuberant 
mass  at  the  earth's  equator.  It  varies  with  the  configurations 
of  the  sun,  moon,  and  moon's  node,  and  is  represented  by  sup- 
posing the  extremity  of  the  earth's  axis  to  describe  a  minute 
ellipse  in  the  heavens,  in  about  nineteen  years,  while  it  is  car- 
ried forward  in  its  general  revolution  about  the  pole  of  the  eclip- 
tic. The  exact  numerical  value  of  nutation,  as  determined  by 
Busch,  Peters,  and  Lundahl,  is  9".2320. 

Aberration. — If  the  light  which  radiates  from  a  self-luminous 
body,  or  which  is  reflected  from  an  opake  one,  passed  instantly 
from  one  point  in  space  to  any  other,  however  remote,  then 
would  luminous  bodies  actually  occupy  the  places  in  space, 


ABERRATION.  305 

which,  to  the  eye,  they  appear  to  fill.  This,  however,  is  not 
the  case.  Light  has  "been  found  to  progress  with  a  velocity 
amazing  indeed,  but  still  finite,  bringing  with  it  certain  effects, 
which,  in  the  present  state  of  astronomy,  cannot  be  disregarded. 
The  discovery  of  the  finite  velocity  of  light  was  made  by  Roemer, 
from  an  attentive  examination  of  the  eclipses  of  the  satellites  of 
Jupiter.  It  will  be  remembered  that  the  earth's  orbit,  being  en- 
closed within  the  orbit  of  Jupiter,  when  the  earth  and  Jupiter 
are  in  a  straight  line  passing  through  the  sun,  and  on  the  same 
side  of  the  sun,  they  are  nearer  each  other  than  when  on  oppo- 
site sides  of  the  sun,  by  a  distance  equal  to  the  diameter  of  the 
earth's  orbit,  or  by  nearly  200,000,000  of  miles.  It  was  found 
that  those  eclipses  of  Jupiter's  satellites  which  occurred  while 
the  earth  and  Jupiter  were  near  each  other,  came  on  earlier  than 
the  computed  time ;  while  those  occurring  at  the  time  Jupiter 
and  the  earth  were  at  their  greatest  distance,  came  on  too  late 
for  the  computed  time.  For  a  long  time  no  explanation  could 
be  found  for  this  singular  phenomenon.  At  length  it  was  found 
to  depend  on  the  relative  distances  of  the  earth  and  Jupiter,  and 
was  finally  explained  by  giving  to  the  light  which  comes  to  us 
from  the  satellites  of  that  planet,  a  finite  and  determined  velo- 
city. As  the  light  from  the  satellites  is  reflected  light,  so  soon 
as  the  satellite  enters  the  shadow  of  Jupiter,  the  source  of  light 
is  cut  off;  and  in  case  light  moved  instantly  from  one  point  to 
another,  the  eclipse  would  take  place  the  moment  the  satellite 
entered  the  shadow  of  its  primary.  But  the  stream  of  light  flow- 
ing on  with  a  finite  velocity,  requires  a  certain  time  to  become 
exhausted.  When  Jupiter  and  the  earth  are  nearest,  or  in  con- 
junction, the  stream  is  shorter,  or  has  a  less  distance  to  flow,  by 
nearly  200,000,000  of  miles,  than  when  the  earth  and  planet  are 
in  opposition,  or  most  remote  from  each  other.  In  this  way  it 
is  found  that  light  requires  about  sixteen  minutes  to  cross  the 
diameter  of  the  earth's  orbit.  The  velocity  thus  determined  has 
been  confirmed,  in  a  remarkable  manner,  by  Bradley's  discovery 
of  what  has  been  called  the  aberration  of  the  fixed  stars.  This 
is  an  apparent  change  in  the  places  of  the  fixed  stars,  due  to  the 
fact  that  the  velocity  of  light,  combined  with  that  of  the  earth 
in  its  orbit,  causes  the  fixed  stars  apparently  to  describe  a  mi- 
nute orbit,  in  the  period  of  one  year.  Very  extended  and  minute 
investigations  have  revealed  the  actual  velocity  of  the  light  of  the 
fixed  stars:  and  this  velocity  is  nearly,  if  not  exactly  equal,  to 
that  of  reflected  light  as  deduced  from  the  observed  eclipses  of 
Jupiter's  satellites.  The  numerical  value  of  aberration,  as  last 
determined  by  the  Russian  astronomers,  is  20".50. 

Parallax. — This  subject  has  already  been  treated,  in  the  chap- 
ter on  the  distribution  and  distance  of  the  fixed  stars.  The 
effect  of  parallax  on  the  place  of  any  heavenly  body,  is  to  cause 


306  GEOGRAPHY  OF  THE  HEAVENS. 

it  to  appear  less  elevated  above  the  horizon  than  it  would  be  if 
seen  from  the  earth's  center.  The  apparent  places  of  the  sun, 
moon,  and  planets,  are  sensibly  affected  by  parallax  ;  and  their 
true  places  can  only  be  obtained  from  their  apparent  places,  by 
correcting  these  for  the  effect  of  parallax. 

Refraction. — The  light  which  reaches  us  from  the  heavenly 
bodies  only  comes  to  the  eye  of  the  observer  after  traversing  the 
atmosphere,  a  gaseous  medium,which  possesses  the  power  of  caus- 
ing a  ray  of  light,  while  traversing  it,  to  bend  from  its  rectilinear 
path.  In  consequence  of  this  bending  of  the  rays  of  light,  called 
refraction,  a  star  or  planet  is  seen  in  the  direction  of  the  straight 
line  drawn  tangent  to  the  curved  ray  of  light,  at  the  point  where 
it  enters  the  eye ;  and  it  thus  appears  higher  above  the  horizon 
than  it  really  is.  Thus  a  star  or  planet  is  seen,  by  the  eye, 
while  it  is  yet  really  below  the  horizon,  in  consequence  of  re- 
fraction. The  same  cause  diffuses  the  light  of  day,  and  gives 
to  us  the  twilight  of  morning  and  evening.  The  effect  of  refrac- 
tion on  the  places  of  the  heavenly  bodies  has  been  carefully 
studied,  and  tables  have  been  prepared,  showing  the  value  of 
refraction  at  all  elevations  above  the  horizon,  and  for  all  changes 
of  the  thermometer  and  barometer. 

To  obtain,  then,  the  absolute  place  of  any  heavenly  body, 
from  its  apparent  place,  as  taken  by  an  instrument  absolutely 
perfect,  we  must  correct  its  instrumental,  or  observed  place,  for 
precession,  nutation,  aberration,  parallax,  and  refraction.  If  the 
instrument  be  not  absolutely  perfect,  then  must  its  errors  be  in- 
vestigated, and  be  allowed  for,  before  a  final  reliable  result  can 
be  obtained. 


THE  TIDES.  307 


CHAPTER   X. 

THE  TIDES. 

THE  oceans,  and  all  the  seas,  are  observed  to  be  incessantly 
agitated  for  certain  periods  of  time;  first  from  the  east  toward 
the  west,  and  then  again  from  the  west  toward  the  east.  In  this 
motion,  which  lasts  about  six  hours,  the  sea  gradually  swells; 
so  that  entering  the  mouths  of  rivers,  it  drives  back  the  waters 
toward  their  source.  After  a  continual  flow  of  six  hours,  the 
seas  seem  to  rest  for  about  a  quarter  of  an  hour ;  they  then  be- 
gin to  ebb,  or  retire  back  again  from  west  to  east  for  six  hours 
more ;  and  the  rivers  again  resume  their  natural  courses.  Then, 
after  a  seeming  pause  of  a  quarter  of  an  hour,  the  seas  again 
begin  to  flow,  as  before,  and  thus  alternately.  This  regular  al- 
ternate motion  of  the  sea  constitutes  the  tides,  of  which  there 
are  two  in  something  less  than  twenty-five  hours. 

The  ancients  considered  the  ebbing  and  flowing  of  the  tides  as  one  of 
the  greatest  mysteries  in  nature,  and  were  utterly  at  a  loss  to  account  for 
them.  Galileo  and  Descartes,  and  particularly  Kepler,  made  some  suc- 
cessful advances  toward  ascertaining  the  cause ;  but  Sir  Isaac  Newton 
was  the  first  who  clearly  showed  what  were  the  chief  agents  in  producing 
these  motions. 

The  cause  of  the  tides,  is  the  attraction  of  the  sun  and  moon, 
but  chiefly  of  the  moon,  upon  the  waters  of  the  ocean.  In  vir- 
tue of  gravitation,  the  moon,  by  her  attraction,  draws,  or  raises 
the  water  toward  her;  but  because  the  power  of  attraction  di- 
minishes as  the  squares  of  the  distance  increase,  the  waters  on 
the  opposite  side  of  the  earth  are  not  so  much  attracted  as  they 
are  on  the  side  nearest  the  moon. 

That  the  moon,  says  Sir  John  Herschel,  should,  by  her  attraction,  heap 
up  the  waters  of  the  ocean  under  her,  seems  to  most  persons  very  na- 
tural ;  but  that  the  same  cause  should,  at  the  same  time,  heap  them  up 
on  the  opposite  side,  seems,  to  many,  palpably  absurd.  Yet  nothing  is 
more  true,  nor  indeed  more  evident,  when  we  consider  that  it  is  not  by 
her  whole  attraction,  but  by  the  differences  of  her  attractions  at  the  oppo- 
site surfaces  and  at  the  center,  that  the  waters  are  raised. 

That  the  tides  are  dependent  upon  some  known  and  determinate  laws, 
is  evident  from  the  exact  time  of  high  water  being  previously  given  in 
every  ephemeris,  and  in  many  of  the  common  almanacs. 

The  moon  comes  every  day  later  to  the  meridian  than  on  the  day  pre- 
ceding, and  her  exact  time  is  known  by  calculation ;  and  the  tides  in  any 


SOS 


GEOGRAPHY  OF  THE  HEAVENS. 


and  every  place,  will  be  found  to  follow  the  same  rule ;  happening  ex- 
actly so  much  later  every  day  as  the  moon  comes  later  to  the  meridian. 
From  this  exact  conformity  to  the  motions  of  the  moon,  we  are  induced 
to  look  to  her  as  the  cause ;  and  to  infer  that  these  phenomena  are  occa- 
sioned principally  by  the  moon's  attraction. 


THE    TIDES. 


FIG.  l.  Fis.  2.  FIG.  3. 

If  the  earth  were  at  rest,  and  there  were  no  attractive  influ- 
ence from  either  the  sun  or  moon,  it  is  obvious  from  the  princi- 
ples of  gravitation,  that  the  waters  in  the  ocean  would  be  truly 
spherical  (as  represented  by  figure  1)  ;  but  daily  observation 
proves  that  they  are  in  a  state  of  continual  agitation. 

If  the  earth  and  moon  were  without  motion,  and  the  earth 
covered  all  over  with  water,  the  attraction  of  the  moon  would 
raise  it  up  in  a  heap  in  that  part  of  the  ocean  to  which  the  moon 
is  vertical,  as  in  figure  2,  and  there  it  would,  probably,  always 
continue ;  but  by  the  rotation  of  the  earth  upon  its  axis,  each 
part  of  its  surface  to  which  the  moon  is  vertical  is  presented  to 
the  action  of  the  moon:  wherefore,  as  the  quantity  of  water  on 
the  whole  earth  remains  the  same,  when  the  waters  are  elevated 
on  the  side  of  the  earth  under  the  moon,  and  on  the  opposite 
side  also,  it  is  evident  they  must  recede  from  the  intermediate 
points,  and  thus  the  attraction  of  the  moon  produce  high  water 
at  two  opposite  places,  and  low  water  at  two  opposite  places  on 
the  earth  at  the  same  time,  as  represented  by  figure  3. 

This  is  evident  from  the  figure.  The  waters  cannot  rise  in  one  place, 
without  falling  in  another ;  and  therefore  they  must  fall  as  low  in  the 
horizon,  at  C  and  D,  as  they  rise  in  the  zenith  and  nadir,  at  A  and  B, 
as  in  the  following  figure. 


It  has  already  been  shown,  under  the  article  gravitation,  that 
the  earth  and  moon  would  fall  toward  each  other,  by  the  power 
of  their  mutual  attraction,  if  there  were  no  centrifugal  force  to 


THE  TIDES.  309 

prevent  them;  and  that  the  moon  would  fall  as  much  faster  to- 
ward the  earth  than  the  earth  would  fall  toward  the  moon,  as  the 
quantity  of  matter  in  the  earth  is  greater  than  the  quantity  of 
matter  in  the  moon.  The  same  law  determines  also  the  size  of 
their  respective  orbits  around  their  common  center  of  gravity. 

It  follows,  then,  as  we  have  seen,  that  the  moon  does  not  revolve, 
strictly  speaking,  around  the  earth  as  a  center,  but  around  a  point  be- 
tween them,  which  is  80  times  nearer  the  earth  than  the  moon,  and  con- 
sequently is  situated  about  3000  miles  from  the  earth's  center.  It  has 
also  been  shown,  that  all  bodies  moving  in  circles  acquire  a  centrifugal 
force  proportioned  to  their  respective  masses  and  velocity.  From  these 
facts,  some  philosophers  account  for  high  water  on  the  side  of  the  earth 
opposite  to  the  moon,  in  the  following  manner : 

As  the  earth  and  moon  move  around  their  common  center  of  gravity, 
that  part  of  the  earth  which  is  at  any  time  turned  from  the  moon,  being 
about  7000  miles  farther  from  the  center  of  gravity  than  the  side  next 
the  moon,  would  have  &  greater  centrifugal  force  than  the  side  next  her. 
At  the  earth's  center,  the  centrifugal  force  will  balance  the  attractive  force ; 
therefore,  as  much  water  is  thrown  off"  by  the  centrifugal  force  on  the 
side  which  is  turned  from  the  moon,  as  is  ^sed  on  the  side  next  her  by 
her  attraction. 

From  the  universal  law,  that  the  force  of  gravity  diminishes 
as  the  square  of  the  distance  increases,  it  results  that  the  attrac- 
tive power  of  the  moon  decreases  in  intensity  at  every  step  of 
the  descent  from  the  zenith  to  the  nadir;  and,  consequently,  that 
the  waters  on  the  zenith,  being  more  attracted  by  the  moon  than 
the  earth  is  at  its  center,  move  faster  toward  the  moon  than  the 
earth's  center  does :  and  as  the  center  of  the  earth  moves  faster 
toward  the  moon  than  the  waters  about  the  nadir  do,  the  waters 
will  be,  as  it  were,  left  behind,  and  thus,  with  respect  to  the 
center,  they  will  be  raised. 

The  reason  why  the  earth  and  waters  of  our  globe  do  not  seem  to  be 
affected  equally  by  the  moon's  attraction,  is,  that  the  earthy  substance  of 
the  globe,  being  firmly  united,  does  not  yield  to  any  difference  of  the 
moon's  attractive  force  ;  insomuch  that  its  upper  and  lower  surface  must 
move  equally  fast  toward  the  moon  ;  whereas  the  waters,  cohering  toge- 
ther but  very  slightly,  yield  to  the  different  degrees  of  the  moon's  attrac- 
tive force,  at  different  distances  from  her. 

The  length  of  a  lunar  day,  that  is,  of  the  interval  from  one 
meridian  passage  of  the  moon  to  another,  being,  at  a  mean  rate, 
24  hours,  48  minutes,  and  44  seconds,  the  interval  between  the 
flux  and  the  reflux  of  the  sea  is  not,  at  a  mean  rate,  precisely  six 
hours,  but  twelve  minutes  and  eleven  seconds  more,  so  that  the 
time  of  high  water  does  not  happen  at  the  «ame  hour,  but  is 
about  49  minutes  later  every  day. 

The  earth  revolves  on  its  axis  m  about  twenty-four  hours ;  if 
the  moon,  therefore,  were  stationary,  the  same  part  of  our  globe 


310  GEOGRAPHY  OF   THE  HEAVENS. 

would  return  beneath  it,  and  there  would  be  two  tides  every 
twenty-four  hours ;  but  while  the  earth  is  turning  once  upon  its 
axis,  the  moon  has  gone  forward  13°  in  her  orbit,  which  takes 
forty-nine  minutes  more  before  the  same  meridian  is  brought 
again  directly  under  the  moon.  And  hence  every  succeeding 
day  the  time  of  high  water  will  be  forty-nine  minutes  later  than 
the  preceding. 

For  example : — Suppose  at  any  place  it  be  high  water  at  3  o'clock  in 
the  afternoon,  upon  the  day  of  new  moon ;  the  following  day  it  will  be 
high  water  about  49  minutes  after  3 ;  the  day  after,  about  M8  minutes 
after  4 ;  and  so  on  till  the  next  new  moon.  The  exact  daily  mean  retar- 
dation of  the  tides  is  thus  determined  : 

The  mean  motion  of  the  moon,  in  a  solar  day.  is    ]  3°.  1 76:>96:39 
The  mean  motion  of  the  sun,  in  a  solar  day.  is         0  .98564722 

Now,  as  15°  is  to  60  minutes,  so  is  12°.]  9074917  to  48'  44". 

It  is  obvious  that  the  attraction  of  the  sun  must  produce  upon 
the  waters  of  the  ocean  a  like  effect  to  that  of  the  moon,  though 
in  a  less  degree;  for  the  great  mass  of  the  sun  is  more  than 
compensated  by  its  immense  distance.  Nevertheless,  its  effect 
is  considerable,  and  it  can  be  shown,  that  the  bight  of  the  solar 
tide  is  to  the  night  of  the  lunar  tide  as  2  to  5.  Hence  the  tides, 
though  constant,  are  not  equal.  They  are  greatest  when  the 
moon  is  in  conjunction  with,  or  in  opposition  to,  the  sun,  and 
least  when  in  quadrature.  For,  in  the  former  case,  the  sun  and 
moon  set  together,  and  the  tide  will  equal  the  sum  of  the  solar 
and  lunar  tides,  and  in  the  latter  they  act  against  each  other, 
and  the  tide  will  be  the  difference. 

The  former  are  called  spring  tides ;  the  latter,  neap  tides.  The 
spring  tides  are  highest  when  the  sun  and  moon  are  near  the 
equator,  and  the  moon  at  her  least  distance  from  the  earth.  The 
neap  tides  are  lowest  when  the  moon,  in  her  first  and  second 
quarter's,  is  at  her  greatest  distance  from  the  earth.  The  general 
theory  of  the  tides  is  this :  when  the  moon  is  nearest  the  earth, 
her  attraction  is  strongest,  and  the  tides  are  the  highest;  when 
she  is  farthest  from  the  earth,  her  attraction  is  least,  and  the 
tides  are  the  lowest. 

From  the  above  theory,  it  might  be  supposed  that  the  tides 
would  be  the  highest  when  the  moon  was  on  the  meridian.  But 
it  is  found  that  in  open  seas,  where  the  water  flows  freely,  the 
moon  has  generally  passed  the  north  or  south  meridian  about  three 
hours  when  it  is  high  water.  The  reason  is,  that  the  force  by 
which  the  moon  raises  the  tide  continues  to  act,  and  consequently 
the  waters  continue  to  rise  after  she  has  passed  the  meridian. 

For  the  same  reason,  the  highest  tides,  which  are  produced  by 
the  conjunction  and  opposition  of  the  sun  and  moon,  do  not  hap- 
pen on  the  days  of  the  full  and  change;  neither  do  the  lowest 
tides  happen  on  the  days  of  their  quadratures. — But  the  greatest 


THE  TIDES.  311 

spring  tides  commonly  happen  l£  days  after  the  new  and  full 
moons;  and  the  least  neap  tides  1$  days  after  the  first  and  third 
quarters. 

The  sun  and  moon,  by  reason  of  the  elliptical  form  of  their  orbits,  are 
alternately  nearer  to  and  farther  from  the  earth,  than  their  mean  distances. 
In  consequence  of  this,  the  efficacy  of  the  sun  will  fluctuate  between  the 
extremes  19  and  21,  taking  20  for  its  mean  value;  and  between  43 
and  59  for  that  of  the  moon.  Taking  into  account  this  cause  of  differ- 
ence, the  highest  spring  tide  will  be  to  the  lowest  neap  as  59-J-21  is  to 
43 — 19,  or  as  80  to  24,  or  10  to  3.  The  relative  mean  influence  is  as 
61  to  20,  or  as  5  to  2,  nearly. — HerscheFs  Astr.  p.  339. 

Though  the  tides,  in  open  seas,  are  at  the  highest  about  three 
hours  after  the  moon  has  passed  the  meridian,  yet.  the  waters  in 
their  passage  through  shoals  and  channels,  and  by  striking 
against  capes  and  headlands,  are  so  retarded  that,  to  different 
places,  the  tides  happen  at  all  distances  of  the  moon  from  the 
meridian  ;  consequently  at  all  hours  of  the  lunar  day. 

In  small  collections  of  water,  the  moon  acts  at  the  same  time 
on  every  part ;  diminishing  the  gravity  of  the  whole  mass.  On 
this  account  there  are  no  sensible  tides  in  lakes,  they  being  gen- 
erally so  small  that  when  the  moon  is  vertical,  it  attracts  every 
part  alike ;  and  by  rendering  all  the  waters  equally  light,  no 
part  of  them  can  be  raised  higher  than  another.  The  Mediterra- 
nean and  Baltic  seas  have  very  small  elevations,  partly  for  this 
reason,  and  partly  because  the  inlets  by  which  they  communi- 
cate with  the  ocean  are  so  narrow,  that  they  cannot,  in  so  short 
a  time,  either  receive  or  discharge  enough,  sensibly  to  raise  or 
sink  their  surfaces. 

Of  all  the  causes  of  difference  in  the  hight  of  tides  at  different 
places,  by  far  the  greatest  is  local  situation.  In  wide-mouthed 
rivers,  opening  in  the  direction  of  the  stream  of  the  tides,  and 
whose  channels  are  growing  gradually  narrower,  the  water  is 
accumulated  by  the  contracting  banks,  until  in  some  instances 
it  rises  to  the  hight  of  20,  30,  and  even  50  feet. 

Air  being  lighter  than  water,  and  the  surface  of  the  atmosphere 
being  nearer  to  the  moon  than  the  surface  of  the  sea,  it  cannot 
be  doubted  but  that  the  moon  raises  much  higher  tides  in  the 
atmosphere  than  in  the  sea.  According  to  Sir  John  Herschel, 
these  tides  are,  by  very  delicate  observations,  rendered  not  only 
sensible,  but  measurable. 

Upon  the  supposition  that  the  waters  on  the  surface  of  the  moon  are 
of  the  same  specific  gravity  as  our  own,  we  might  easily  determine  the 
hight  to  which  the  earth  would  raise  a  lunar  tide,  by  the  known  principle, 
that  the  attraction  of  one  of  these  bodies  on  the  other's  surface  is  directly 
as  its  quantity  of  matter,  and  inversely  as  its  diameter.  By  making  the 
calculation,  we  shall  find  the  attractive  power  of  the  earth  upon  the  moon 
to  be  21.777  times  greater  than  that  of  the  moon  upon  the  earth. 


3)2        GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTER    XI. 

THE  SEASONS— DIFFERENT  LENGTHS  OF  THE  DAYS  AND 
NIGHTS. 

THE  vicissitudes  of  the  seasons  and  the  unequal  lengths  of 
the  days  and  nights,  are  occasioned  by  the  annual  revolution  ol 
the  earth  around  the  sun,  with  its  axis  inclined  to  the  plane  oi 
its  orbit. 

The  temperature  of  any  part  of  the  earth's  surface  depends 
mainly,  if  not  entirely,  upon  its  exposure  to  the  sun's  rays. 
Whenever  the  sun  is  above  the  horizon  of  any  place,  that  place 
is  receiving  heat;  when  the  sun  is  below  the  horizon,  it  is  parting 
with  it,  by  a  process  which  is  called  radiation.  The  quantities 
of  heat  thus  received  and  imparted  in  the  course  of  the  year, 
must  balance  each  other  at  every  place,  or  the  equilibrium  of 
temperature  would  not  be  supported. 

Whenever,  then,  the  sun  remains  more  than  twelve  hours 
above  the  horizon  of  any  place,  and  less  beneath,  the  general 
temperature  of  that  place  will  be  above  the  mean  state;  when 
the  reverse  takes  place,  the  temperature,  for  the  same  reason, 
will  be  below  the  mean  state.  Now  the  continuance  of  the  sun 
above  the  horizon,  of  any  place,  depends  entirely  upon  his  decli- 
nation, or  altitude  at  noon.  About  the  20th  of  March,  when  the 
sun  is  in  the  vernal  equinox,  and  consequently  has  no  declination, 
he  rises  at  six  in  the  morning  and  sets  at  six  in  the  evening; 
the  day  and  night  are  then  equal,  and  as  the  sun  continues  as 
long  above  our  horizon  as  below  it,  his  influence  must  be  nearly 
the  same  at  the  same  latitudes,  in  both  hemispheres. 

From  the  20th  of  March  to  the  21st  of  June,  the  days  grow 
longer,  and  the  nights  shorter;  in  the  northern  hemisphere  the 
temperature  increases,  and  we  pass  from  spring  to  mid-summer; 
while  the  reverse  of  this  takes  place  in  the  southern  hemisphere. 
From  the  21st  of  June  to  the  23d  of  September,  the  days  and 
nights  again  approach  to  equality,  and  the  excess  of  temperature 
in  the  northern  hemisphere  above  the  mean  state,  grows  less,  as 
also  its  defect  in  the  southern ;  so  that,  when  the  sun  arrives  a. 
the  autumnal  equinox,  the  mean  temperature  is  again  restored. 
From  the  23d  of  September  until  the  21st  of  December,  our 
nights  grow  longer  and  the  days  shorter,  and  the  cold  increases 


THE    SEASONS.  313 

as  before  it  diminished;  while  we  pass  from  autumn  to  mid 
winter,  in  the  northern  hemisphere,  and  the  inhabitants  of  the 
southern  hemisphere  from  spring  to  mid-summer.  From  the 
21st  of  December  to  the  20th  of  March,  the  cold  relaxes  as  the 
days  grow  longer,  and  we  pass  from  the  dreariness  of  winter  to 
the  mildness  of  spring,  when  the  seasons  are  completed,  and  the 
mean  temperature  is  again  restored.  The  same  vicissitudes  trans- 
pire, at  the  same  time,  in  the  southern  hemisphere,  but  in  a 
contrary  order. — Thus  are  produced  the  four  seasons  of  the  year. 

But  I  have  stated  not  the  only,  nor,  perhaps,  the  most  efficient 
cause  in  producing  the  heat  of  summer  and  the  cold  of  winter. 
If,  to  the  inhabitants  of  the  equator,  the  sun  were  to  remain  16 
hours  below  their  horizon,  and  only  8  hours  above  it,  for  every 
day  of  the  year,  it  is  certain  they  would  never  experience  the 
rigors  of  our  winter ;  since  it  can  be  demonstrated,  that  as  much 
heat  falls  upon  the  same  area  from  a  vertical  sun,  in  8  hours,  as 
would  fall  from  him  at  an  angle  of  60°,  in  16  hours. 

Now  as  the  sun's  rays  fall  most  obliquely  when  the  days  are 
shortest ,  and  most  directly  when  the  days  are  longest ,  these  two 
causes,  namely,  the  duration  and  intensity  of  the  solar  heat, 
together,  produce  the  temperature  of  the  different  seasons.  The 
reason  why  we  have  not  the  hottest  temperature  when  the  days 
are  longest,  and  the  coldest  temperature  when  the  days  are 
shortest,  but  in  each  case  about  a  month  afterwards,  appears  to 
be,  that  a  body  once  heated,  does  not  grow  cold  instantaneously, 
but  gradually,  and  so  of  the  contrary.  Hence,  as  long  as  more 
heat  comes  from  the  sun  by  day  than  is  lost  by  night,  the  heat 
will  increase,  and  vice  versa. 

The  north  pole  of  the  earth  is  denominated  the  elevated  pole, 
because  it  is  always  about  23^°  above  a  perpendicular  to  the 
plane  of  the  equator,  and  the  south  pole  is  denominated  the  de- 
pressed pole,  because  it  is  about  the  same  distance  below  such 
perpendicular. 

As  the  sun  cannot  shine  on  more  than  one  half  the  earth's 
surface  at  a  time,  it  is  plain,  that  when  the  earth  is  moving 
through  that  portion  of  its  orbit  which  lies  above,  the  sun,  the 
elevated  pole  is  in  the  dark.  This  requires  six  months,  that  is, 
until  tlie  earth  arrives  at  the  equinox,  when  the  elevated  pole 
emerges  into  the  light,  and  the  depressed  pole  is  turned  away 
from  the  sun  for  the  same  period.  Consequently,  there  are  six 
months  day  and  six  months  night,  alternately,  at  the  poles. 

When  the  sun  appears  to  us  to  be  in  one  part  of  the  ecliptic, 
the  earth,  as  seen  from  the  sun,  appears  in  the  point  diametri- 
cally opposite.  Thus,  when  the  sun  appears  in  the  vernal  equi- 
nox at  the  first  point  of  Aries,  the  earth  is  actually  in  the  oppo- 
site equinox  at  Libra.  The  days  and  nights  are  then  equal  all 
over  the  world. 

80 


314  GEOGRAPHY  OF  THE  HEAVENS. 

As  the  sun  appears  to  move  up  from  the  vernal  equinox  to  the 
summer  solstice,  the  earth  actually  moves  from  the  autumnal 
equinox  down  to  the  winter  solstice.  The  days  now  lengthen 
in  the  northern  hemisphere,  and  shorten  in  the  southern.  The 
sun  is  now  over  the  north  pole,  where  it  is  mid-day,  and  oppo- 
site the  south  pole,  where  it  is  mid-night. 

As  the  sun  descends  from  the  summer  solstice  toward  the 
autumnal  equinox,  the  earth  ascends  from  the  winter  solstice 
toward  the  vernal  equinox.  The  summer  days  in  the  northern 
hemisphere  having  waxed  shorter  and  shorter,  now  become 
again  of  equal  length  in  both  hemispheres. 

While  the  sun  appears  to  move  from  the  autumnal  equinox 
down  to  the  winter  solstice,  the  earth  passes  up  from  the  vernal 
equinox  to  the  summer  solstice;  the  south  pole  comes  into  the 
light,  the  winter  days  continually  shorten  in  the  northern  hemi- 
sphere, and  the  summer  days  as  regularly  increase  in  length  in 
the  southern  hemisphere. 

While  the  sun  appears  again  to  ascend  from  its  winter  sol- 
stice to  the  vernal  equinox,  the  earth  descends  from  the  summer 
solstice  to  the  autumnal  equinox.  The  summer  days  now 
shorten  in  the  southern  hemisphere,  and  the  winter  days  lengthen 
in  the  northern  hemisphere. 

When  the  sun  passes  the  vernal  equinox,  it  rises  to  the  arctic 
or  elevated  pole,  and  sets  to  the  antarctic  pole.  When  the  sun 
arrives  at  the  summer  solstice,  it  is  noon  at  the  north  pole,  and 
midnight  at  the  south  pole.  When  the  sun  passes  the  autumnal 
'equinox,  it  sets  to  the  north  pole,  and  rises  to  the  south  pole. 
When  the  sun  arrives  at  the  winter  solstice,  it  is  midnight  at 
the  north  pole,  and  noon  at  the  south  pole ;  and  when  the  sun 
comes  again  to  the  vernal  equinox,  it  closes  the  day  at  the  south 
pole,  and  lights  up  the  morning  at  the  north  pole. 

There  would,  therefore,  be  186^  days  during  which  the  sun 
would  not  set  at  the  north  pole,  and  an  equal  time  during  which 
he  would  not  rise  at  the  south  pole;  and  178^  days  in  which  he 
would  not  set  at  the  south  pole,  nor  rise  at  the  north  pole. 

At  the  arctic  circle,  23°  27^'  from  the  pole,  the  longest  day  is 
24  hours,  and  goes  on  increasing  as  you  approach  the  pole.  In 
latitude  67°  18'  it  is  30  days;  in  lat.  69°  30'  it  is  60  days,  &c. 
The  same  takes  place  between  the  antarctic  circle  and  the  south 
pole,  with  the  exception,  that  the  day  in  the  same  latitude  south 
is  a  little  shorter,  since  the  sun  is  not  so  long  south  of  the  equa- 
tor, as  at  the  north  of  it.  In  this  estimate  no  account  is  taken 
of  the  refraction  of  the  atmosphere,  which,  as  we  shall  see 
hereafter,  Increases  the  length  of  the  day,  by  making  the  sun 
appear  more  elevated  above  the  horizon  than  it  really  is. 


LENGTHS  OF  DAYS  AND  NIGHTS. 


315 


THE  SEASONS— UNEQUAL  LENGTHS  OF  DAYS  AND  NIGHTS. 

fcrf* 


The  above  cut  represents  the  inclination  of  the  earth's  axis  to  its  orbit 
in  every  one  of  the  twelve  signs  of  the  ecliptic,  and  consequently  for  each 
month  in  the  year.  The  sun  enters  the  sign  Aries,  or  the  vernal  equi- 
nox, on  the  20th  of  March,  when  the  earth's  axis  inclines  neither  toward 
the  sun,  nor  from  it,  but  sidewise  to  it ;  so  that  the  sun  then  shines 
equally  upon  the  earth  from  pole  to  pole,  and  the  days  and  nights  are 
everywhere  equal.  This  is  the  beginning  of  the  astronomical  year;  it  is 
also  the  beginning  of  day  at  the  north  pole,  which  is  just  coming  into 
light,  and  the  end  of  day  at  the  south  pole,  which  is  just  going  into 
darkness. 

By  the  earth's  orbital  progress,  the  sun  appears  to  enter  the  second 
sign,  Taurus,  on  the  20th  of  April,  when  the  north  pole,  N,  has  sensibly 
advanced  into  the  light,  while  the  south  pole,  S,  has  been  declining  from 
it ;  whereby  the  days  become  longer  than  the  nights  in  the  northern 
hemisphere,  and  shorter  in  the  southern. 

On  the  21st  of  May,  the  sun  appears  to  enter  the  sign  Gemini,  when 
the  north  pole,  IV,  has  advanced  considerably  further  into  the  light,  while 
the  south  pole,  S,  has  proportionally  declined  from  it ;  the  summer  days 
are  now  waxing  longer  hi  the  northern  hemisphere,  and  the  nights 
shorter. 

The  2 1st  of  June,  when  the  sun  enters  the  sign  Cancer,  is  the  first 
day  of  summer,  in  the  astronomical  year,  and  the  longest  day  in  the 
northern  hemisphere.  The  north  pole  now  has  its  greatest  inclination 
to  the  sun,  the  light  of  which,  as  is  shown  by  the  boundary  of  light  and 
darkness,  in  the  figure,  extends  to  the  utmost  verge  of  the  Arctic  Circle  ; 
the  whole  of  which  is  included  in  the  enlightened  hemisphere  of  the 
earth.,  and  enjoys,  at  this  season,  constant  day  during  the  complete  revo- 


316  GEOGRAPHY  OF  THE  HEAVENS. 

lution  of  the  earth  on  its  axis.  The  whole  of  the  northern  Frigid  Zone 
is  now  in  the  circle  of  perpetual  illumination. 

On  the  23d  of  July,  the  sun  enters  the  sign  Leo  ,•  and  as  the  line  of 
the  earth's  axis  always  continues  parallel  to  itself,  the  boundary  of  light 
and  darkness  begins  to  approach  nearer  to  the  poles,  and  the  length  of 
the  day  in  the  northern  hemisphere,  which  had  arrived  at  its  maximum, 
begins  gradually  to  decrease.  On  the  23d  of  August,  the  sun  enters  the 
sign  Virgo,  increasing  the  appearances  mentioned  in  Leo. 

On  the  23d  of  September,  the  sun  enters  Libra,  the  first  of  the  au- 
tumnal signs,  when  the  earth's  axis,  having  the  same  inclination  as  it  had 
in  the  opposite  sign,  Aries,  is  turned  neither  from  the  sun,  nor  toward  it, 
but  obliquely  to  it,  so  that  the  sun  again  now  shines  equally  upon  the 
whole  of  the  earth's  surface  from  pole  to  pole.  The  days  and  nights  are 
once  more  of  equal  length  throughout  the  world. 

On  the  23d  of  October,  the  sun  enters  the  sign  Scorpio  ,•  the  days  visi- 
bly decrease  in  length  in  the  northern  hSmisphere,  and  increase  in  the 
southern. 

On  the  22d  of  November,  the  sun  enters  the  sign  Sagittarius,  the  last 
of  the  autumnal  signs,  at  which  time  the  boundary  of  light  and  darkness 
is  at  a  considerable  distance  from  the  north  pole,  while  the  south  pole  has 
proportionally  advanced  into  the  light ;  the  length  of  the  day  continues 
to  increase  in  the  southern  hemisphere,  and  to  decrease  in  the  northern. 

On  the  2 1st  of  December,  which  is  the  period  of  the  winter  solstice, 
the  sun  enters  the  sign  Capricorn.  At  this  time,  the  north  pole  of  the 
earth's  axis  is  turned  from  the  sun  into  perpetual  darkness ;  while  the 
south  pole,  in  its  turn,  is  brought  into  the  light  of  the  sun,  whereby  tha 
whole  Antarctic  region  comes  into  the  circla  of  perpetual  illumination. 
It  is  now  that  the  southern  hemisphere  enjoys  all  those  advantages  with 
which  the  northern  hemisphere  was  favored  on  the  21st  of  June;  while 
the  northern  hemisphere,  in  its  turn,  undergoes  the  dreariness  of  winter, 
with  short  days  and  long  nights. 


AURORA  BOREALIS.  317 


CHAPTEK  XII. 

AURORA  BOREALIS 

THE  sublime  and  beautiful  phenomena  presented  by  tbe  aurora 
borealis,  or  northern  lights,  as  they  are  called,  have  been  in  all 
ages  a  source  of  admiration  and  wonder  alike  to  the  peasant  and 
the  philosopher.  In  the  regions  of  the  north,  they  are  regarded 
by  the  ignorant  with  superstitious  dread,  as  harbingers  of  evil ; 
while  all  agree  in  placing  them  among  the  unexplained  wonders 
of  nature. 

These  lights,  or  meteoric  coruscations,  are  more  brilliant  in 
the  arctic  regions,  appearing  mostly  in  the  winter  season  and  in 
frosty  weather.  They  commonly  appear  at  twilight  near  the 
horizon,  and  sometimes  continue  in  that  state  for  several  hours 
without  any  perceptible  motion;  after  which  they  send  forth 
streams  of  stronger  light,  shooting  with  great  velocity  up  to  the 
zenijh,  emulating,  not  unfrequently,  the  lightning  in  vividness, 
and  the  rainbow  in  coloring;  and  again  silently  rising  in  a  com- 
pact majestic  arch  of  steady  white  light,  apparently  durable  and 
immovable,  and  yet  so  evanescent,  that  while  the  beholder  looks 
upon  it,  it  is  gone. 

At  other  times,  they  cover  the  whole  hemisphere  with  their 
flickering  and  fantastic  coruscations.  On  these  occasions  their 
motions  are  amazingly  quick,  and  they  astonish  the  spectator 
with  rapid  changes  of  form.  They  break  out  in  places  where 
none  were  seen  before,  skimming  briskly  along  the  heavens ; 
then  they  are  suddenly  extinguished,  leaving  behind  a  uniform 
dusky  track,  which  again  is  brilliantly  illuminated  in  the  same 
manner,  and  as  suddenly  left  a  dull  blank.  Some  nights  they 
assume  the  appearance  of  vast  columns ;  exhibiting  on  one  side 
tints  of  the  deepest  yellow,  and  on  the  other,  melting  away  till 
they  become  undistinguishable  from  the  surrounding  sky.  They 
have  generally  a  strong  tremulous  motion  from  end  to  end, 
which  continues  till  the  whole  vanishes. 

Maupertuis  relates  that,  in  Lapland,  "  the  sky  was  sometimes 
tinged  with  so  deep  a  red,  that  the  constellation  Orion  looked  as 
though  it  were  dipped  in  blood,  and  that  the  people  fancied  they 
saw  armies  engaged,  fiery  chariots,  and  a  thousand  prodigies." 
Crmelin  relates  that,  "in  Siberia,  on  the  confines  of  the  icy  sea, 
2c2 


318  GEOGRAPHY  OF  THE  HEAVENS. 

the  spectral  forms  appear  like  rushing  armies;  and  that  the  hiss- 
ing- crackling  noises  of  those  aerial  fire-works  so  terrify  the  dogs 
and  the  hunters,  that  they  fall  prostrate  on  the  ground,  and  will 
not  move  while  the  raging  host  is  passing." 

Kerguelen  describes  *'  the  night,  between  Iceland  and  the  Ferro 
Islands,  as  brilliant  as  the  day,"  the  heavens  being  on  fire  with 
flames  of  red  and  white  light,  changing  to  columns  and  arches, 
and  at  length  confounded  in  a  brilliant  chaos  of  cones,  pyramids, 
radii,  sheaves,  arrows,  and  globes  of  fire. 

But  the  evidence  of  Capt.  Parry  is  of  more  value  than  that  of 
the  earlier  travelers,  as  he  examined  the  phenomena  under  the 
most  favorable  circumstances,  during  a  period  of  twenty-seven 
consecutive  months,  and  because  his  observations  are  uninflu- 
enced by  imagination.  He  speaks  of  the  shifting  figures,  thp 
spires  and  pyramids,  the  majestic  arches,  and  the  sparkling  bands 
and  stars  which  appeared  within  the  arctic  circle,  as  surpassing 
his  powers  of  description.  They  are  indeed  sufficient  to  enlist 
the  superstitious  feelings  of  any  people  not  fortified  by  religion 
and  philosophy. 

The  colors  of  the  polar  lights  are  of  various  tints.  The  rays 
or  beams  are  steel  gray,  yellowish  gray,  pea  green,  celandine 
green,  gold  yellow,  violet  blue,  purple,  sometimes  rose  red, 
crimson  red,  blood  red,  greenish  red,  orange  red,  and  lake  red. 
The  arches  are  sometimes  nearly  black,  passing  into  violet  blue, 
gray,  gold  yellow,  or  white,  bounded  by  an  edge  of  yeUow. 
The  luster  of  these  lights  varies  in  kind  as  well  as  intensity. 
Sometimes  it  is  pearly,  sometimes  imperfectly  vitreous,  some- 
times metallic.  Its  degree  of  intensity  varies  from  a  very  faint 
radiance  to  a  light  nearly  equaling  that  of  the  moon. 

Many  theories  have  been  proposed  to  account  for  this  won- 
derful phenomenon,  but  there  seems  to  be  none  which  is  entirely 
satisfactory.  One  of  the  first  conjectures  on  record,  attributes  it 
to  inflammable  vapors  ascending  from  the  earth  into  the  polar 
atmosphere,  and  there  ignited  by  electricity.  Dr.  Halley  objects 
to  this  hypothesis,  that  the  cause  was  inadequate  to  produce  the 
effect.  He  was  of  opinion  that  the  poles  of  the  earth  were  in 
some  way  connected  with  the  aurora;  that  the  earth  was  hollow, 
having  within  it  a  magnetic  sphere,  and  that  the  magnetic  efflu- 
via, in  passing  from  the  north  to  the  south,  might  become  visible 
in  the  northern  hemisphere. 

That  the  aurora  borealis  is,  to  some  extent,  a  magnetical  phe- 
nomenon, is  thought,  even  by  others,  to  be  pretty  clearly  esta- 
blished by  the  following  considerations : 

1.  It  has  been  observed,  that  when  the  aurora  appears  near 
the  northern  horizon  in  the  form  of  an  arch,  the  middle  of  it  is 
not  in  the  direction  of  the  true  north,  but  in  that  of  the  magnetic 
needle  at  the  place  of  observation ;  and  that  when  the  arch  rises 


AURORA  BOREALIS.  319 

toward  the  zenith,  it  constantly  crosses  the  heavens  at  right  an- 
gles, not  to  the  true  magnetic  meridian. 

2.  When  the  beams  of  the  aurora  shoot  up  so  as  to  pass  the 
zenith,  which  is  sometimes  the  case,  the  point  of  their  converg- 
ence is  in  the  direction  of  the  prolongation  of  the  dipping  needle 
at  the  place  of  observation. 

3.  It  has  also  been  observed,  that  during  the  appearance  of  an 
active  and  brilliant  aurora,  the  magnetic  needle  often  becomes 
restless,  varies  sometimes  several  degrees,  and  does  not  resume 
its  former  position  until  after  several  hours. 

From  these  facts  it  has  been  generally  inferred,  that  the  aurora 
is  in  some  way  connected  with  the  magnetism  of  the  earth ;  and 
that  the  simultaneous  appearance  of  the  meteor,  and  the  disturb- 
ance of  the  needle,  are  either  related  as  cause  and  effect,  or  as 
the  common  result  of  some  more  general  and  unknown  cause. 
Dr.  Young,  in  his  lectures,  is  very  certain  that  the  phenomenon 
in  question  is  intimately  connected  with  electro-magnetism,  and 
ascribes  the  light  of  the  aurora  to  the  illuminated  agency  of 
electricity  upon  the  magnetical  substance. 

It  may  be  remarked,  in  support  of  the  electro-magnetic  theory,  that  in 
magnetism,  the  agency  of  electricity  is  now  clearly  established ;  and  it 
can  hardly  be  doubted  that  the  phenomena,  both  of  electricity  and  mag- 
netism, are  produced  by  one  and  the  same  cause  ;  inasmuch  as  magnet- 
ism may  be  induced  by  electricity,  and  the  electric  spark  has  been  drawn 
from  the  magnet 

Sir  John  Herschel  also  attributes  the  appearance  of  the  aurora 
to  the  agency  of  electricity.  This  wonderful  agent,  says  he, 
which  we  see  in  intense  activity  in  lightning,  and  in  a  feebler 
and  more  diffused  form  traversing  the  upper  regions  of  the  at- 
mosphere in  the  northern  lights,  is  present,  probably,  in  immense 
abundance  in  every  form  of  matter  which  surrounds  us,  but  be- 
comes sensible  only  when  disturbed  by  excitements  of  peculiar 
kinds. 


GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTER    XIII. 

ASTRONOMICAL  INSTRUMENTS. 

THE  rapid  introduction  of  telescopes  into  schools  and  acade- 
mies, as  means  of  instruction,  demands  some  notice  of  the  con- 
struction and  modes  of  using  these  instruments.  The  great  advan- 
tage of  possessing  such  means  of  awakening  interest  and  exciting 
to  study,  will  be  readily  appreciated  when  we  remember  that  the 
actual  sight  of  an  object  through  a  telescope  for  even  a  single 
moment,  produces  an  impression,  through  the  eye,  on  the  mind, 
that  no  labored  description  can  ever  accomplish. 

There  are  two  principal  classes  of  telescopes,  the  Refracting 
and  Reflecting.  In  the  first  class,  the  light  from  the  object 
under  examination  falls  on  a  lens  of  glass,  and  by  refraction  is 
brought  to  a  focus,  forming  an  image  of  the  object  which  is  then 
inspected  through  a  powerful  magnifying  glass  called  the  eye 
piece.  In  the  reflecting  telescope  the  ligrht  falls  on  a  metallic 
speculum  or  highly  polished  mirror  of  such  form  as  to  reflect  the 
light  to  a  focus,  where  the  image  formed  is  examined  with  a 
magnifying  glass.  The  largest  telescopes  which  have  ever  been 
constructed,  are  of  the  reflecting  kind,  and  among  these  may  he 
mentioned  the  Great  Reflector  of  Sir  William  Herschel,  >the 
diameter  of  whose  speculum  was  four  feet,  and  its  focal  length 
forty  feet.  A  much  larger  one  has  recently  been  constructed  by 
Lord  Rosse,  an  Irish  nobleman  of  great  liberality,  skill  and 
science.  The  speculum  of  his  Monster  Reflector,  as  it  has  been 
termed,  is  no  less  than  six  feet  in  diameter!  and  its  focal  length 
is  54  feet.  This  magnificent  instrument  has  accomplished  the 
resolution  of  a  great  number  of  nebulae  into  stars,  which  had 
resisted  the  power  of  all  preceding  instruments.  The  largest 
reflecting  telescope  accurately  mounted  in  the  world,  is  that  in 
the  observatory  of  Mr.  Lasselle,  near  Liverpool.  Its  speculum 
is  about  24  inches  in  diameter. 

For  many  years  reflecting  telescopes  have  been  Httle  used  for 
any  other  purpose  than  mere  gazing,  in  'consequence  of  their 
unwieldly  proportions,  rendering  it  next  to  impossible  to  mount 
them  with  sufficent  accuracy  and  steadiness,  for  the  nicer  meas- 
ures and  observations  of  astronomy.  These  difficulties  seem  to 


ASTRONOMICAL  INSTRUMENTS.  321 

have  been  successfully  overcome  by  Mr.  Lasselle,  and  with  the 
accurate  figure  which  Lord  Rosse  has  been  able  to  give  to  his 
large  specula,  reflectors  may  again  come  into  competition  with 
refractors  as  instruments  for  critical  observation. 

The  largest  and  most  perfect  refracting  telescopes,  have  been 
manufactured  at  the  optical  institute  of  Utzschneider  and 
Frauenhofer,  of  Munich,  Bavaria.  Two  instruments  have  been 
there  constructed,  with  object  glasses  of  about  fifteen  inches 
diameter.  One  of  these  is  at  the  Imperial  Russian  observatory 
at  Pulkova,  near  St.  Petersburgh  ;  the  other  is  now  mounted  in 
the  observatory  at  Cambridge,  New  England.  The  refractor 
of  the  Cincinnati  observatory  has  an  object  glass  of  12  inches 
diameter,  and  a  focal  length  of  17  feet. 

These  large  instruments  are  mounted  with  all  the  perfection 
of  art.  Their  enormous  weight  is  so  perfectly  counterpoised 
and  balanced  in  every  direction,  as  to  be  moved  by  the  slightest 
touch  of  the  observer.  They  are  provided  with  delicate  ma- 
chinery, which  may  be  attached  to  the  telescope,  and  will  give 
to  it  a  motion  such  as  shall  exactly  follow  the  apparent  diurnal 
motion  of  any  object  under  examination.  But  for  this  most 
ingenious  and  beautiful  contrivance,  with  high  magnifying 
powers,  it  would  be  next  to  impossible  to  follow  the  swift  ap- 
parent motion  of  the  heavenly  bodies. 

.  The  Equatorial  telescope,  whether  refracting  or  reflecting,  is 
mounted  in  such  way  as  to  revolve  on  two  principal  axes.  The 
one  called  the  polar  axis,  is  precisely  parallel  to  the  earth's  axis ; 
the  other,  called  the  declination  axis,  is  perpendicular  to  the  first 
in  all  its  positions.  By  revolving  the  telescope  around  the  polar 
axis,  we  follow  the  diurnal  motion  of  the  heavenly  bodies;  by 
moving  the  telescope  around  the  declination  axis,  it  is  carried 
north  or  south,  describing  the  arc  of  a  declination  circle.  The 
two  motions  combined,  enable  the  observer  to  direct  the  telescope 
to  any  point  in  the  heavens. 

The  Hour  Circle,  firmly  attached  to  the  lower  extremity  of  the 
polar  axis,  is  divided  into  hours  and  minutes  of  time,  and  mea- 
sures with  accuracy  any  motion  of  the  telescope  around  the  polar 
axis.  The  Declination  Circle,  fixed  to  the  declination  axis,  is 
divided  into  degrees  and  minutes  of  arc,  and  by  Verniers,  into 
seconds,  rendering  it  possible  to  read  with  accuracy  any  motion 
of  the  telescope  around  the  declination  axis. 

The  Micrometer  is  an  instrument  so  contrived  as  to  measure, 
with  great  accuracy,  the  relative  distances  and  positions  which 
fall  within  the  field  of  the  telescope.  There  are  many  construc- 
tions for  this  purpose,  among  them  Frauenhofer's  wire  micro- 
meter holds  a  high  rank.  Two  delicate  spiders'  webs  are  so 
adjusted  in  the  focus  of  the  eye-piece  of  the  telescope,  that  they 
are  seen  distinctly,  and  appear,  when  illuminated  by  a  small 


322  GEOGRAPHY   OF    THE   HEAVENS. 

lamp,  as  delicate  golden  wires  drawn  across  the  field  of  view. 
The  machinery  bearing  these  wires  is  so  contrived  as  to  enable 
the  observer  to  move  them  parallel  to  themselves,  and  also  to 
revolve  them  around  the  axis  of  the  telescope.  Each  of  these 
motions  is  measured  by  divided  scales,  in  the  most  precise  man- 
ner; and  such  is  the  power  of  the  micrometers  attached  to  the 
large  refractors  now  in  use,  that  the  semi-diameter  of  a  spider's 
web  may  be  measured  with  great  certainty,  or  an  inch  may  be 
divided  into  80,000  equal  parts. 

With  the  micrometer,  the  distance  and  angle  of  position  of 
the  double  stars,  the  diameters  of  the  planets,  of  the  sun  and 
moon,  are  accurately  measured  ;  and  a  variety  of  delicate  obser- 
vations made,  which  could  not  be  accomplished  in  any  other 
way. 

The  mounting  of  large  instruments  is  very  expensive,  when 
attended  with  all  the  accurate  detail  necessary  to  render  them 
useful  as  means  of  accurate  observation.  The  amateur  astrono- 
mer, who  wishes  his  telescope  mounted  merely  for  finding  and 
gazing,  may  accomplish  it  at  a  trifling  expense.  (For  a  de- 
scription of  a  cheap  and  convenient  mounting,  called  the  Paral- 
lactic  Ladder,  see  Mitchel's  Sidereal  Messenger,  Vol.  III.) 

The  Transit  Instrument,  is  a  telescope  firmly  attached  to  an 
axis  perpendicular  to  that  of  the  telescope,  and  passing  through 
its  center.  When  this  axis  is  so  placed  on  permanent  supports 
as  to  be  exactly  level,  and  precisely  east  and  west,  the  telescope 
will,  in  revolving  around  its  axis,  describe  a  great  circle  passing 
north  and  south,  or  will  remain  in  all  positions  in  the  plane  of 
the  meridian.  The  horizontal  axis  is  composed  of  two  hollow 
cones  of  brass  or  other  material,  firmly  attached  to  the  tube  of 
the  telescope,  on  either  side.  In 'the  focus  of  the  eye-piece, 
several  spiders'-webs  are  placed  at  equal  distances  from  each 
other,  and  precisely  vertical  in  position.  These  are  crossed  at 
right  angles  by  one  horizontal  spider's  line.  The  number  of 
vertical  wires,  as  they  are  called,  is  generally  seven.  The 
transit  instrument  is  used  to  determine  the  right  ascension  of  the 
heavenly  bodies,  and  the  principle  of  its  application  is  extremely 
simple,  while  its  actual  use  is  attended  with  great  difficulty,  and 
requires  extraordinary  care  and  skill. 

It  will  be  remembered,  that  the  right  ascension  is  measured 
on  the  equator,  from  the  vernal  equinox  round  through  24  hours 
or  360  degrees.  The  instant  when  the  vernal  equinox  is  on  the 
meridian,  is  the  moment  marked  0  hours  by  a  sidereal  clock,  or 
at  that  moment  the  sidereal  day  begins.  If  an  object  is  found  to 
cross  the  meridian,  passing  the  field  of  the  transit  instrument  and 
its  central  wire,  at  one  hour  seven  minutes  eight  and  three-tenths 
seconds,  sidereal  time,  then  will  this  be  its  right  ascension  in  time. 

To  obtain  the  instant  of  crossing  the  middle  wire,  or  the  mean 


ASTRONOMICAL   INSTRUMENTS.  323 

of  the  wires,  is  the  critical  matter  in  observing  with  the  transit. 
The  observer  so  places  his  telescope,  in  declination,  that  the 
star  to  be  observed  will  enter  the  field  of  view  near  the  horizon- 
tal wire.  About  the  time  of  its  appearance,  he  takes  the  second 
from  the  clock,  and,  counting  the  beats,  notes  at  what  beat,  and 
fraction  of  a  beat,  the  star  passes  each  of  the  seven  vertical 
wires.  By  adding  together  these  times,  and  dividing  by  seven, 
he  obtains  the  instant  at  which  the  star  crossed  an  imaginary 
wire  called  the  mean  of  the  wires.  This,  corrected,  for  the 
various  errors  to  which  the  clock  and  transit  instrument  are  liable, 
will  give  the  apparent  right  ascension  of  the  object  observed. 
The  principal  errors  of  the  transit,  are  the  following  : — 1st.,  error 
of  level,  arising  from  the  fact  that  the  horizontal  axis  is  not  pre- 
cisely level,  and,  in  case  the  east  end  is  highest,  the  telescope 
will  look  too  much  west,  and  the  reverse,  if  the  west  end  be 
high.  2d.,  Error  of  azimuth^  occasioned  by  the  horizontal  axis 
not  being  located  precisely  east  and  west.  If  the  east  end  of 
the  axis  be  a  little  north  of  east,  then  the  telescope,  looking 
north  of  the  zenith,  will  point  west  of  the  meridian  ;  looking 
south  of  the  zenith,  it  will  point  east  of  the  meridian.  3d.,  error 
of  collimation,  arising  from  a  failure  to  make  the  axis  of  the 
telescope  precisely  perpendicular  to  the  horizontal  axis  on  which 
it  revolves.  This  error  may  cause  the  instrument  to  look  either 
too  much  east  or  west,  as  the  axis  inclines  in  the  one  or  the 
other  direction. 

The  Transit  Circle  is  an  instrument  like  a  transit  telescope, 
bearing  on  its  horizontal  axis  a  graduated  circle,  by  means  of 
which  the  position  of  the  instrument,  in  declination,  may  be  read 
with  accuracy.  Such  an  instrument  enables  the  observer  to 
determine  both  the  right  ascension  and  declination  of  the  object 
under  examination,  at  the  same  observation. 

These  are  called  fixed,  or  meridian  instruments,  because,  un- 
like the  equatorial,  which  may  be  directed  to  any  point  in  the 
heavens,  they  move  only  in  the  plane  of  the  meridian. 

There  are  many  other  astronomical  instruments,  but  our  limits 
will  not  permit,  in  this  place,  a  more  extended  notice.  The 
only  object  has  been,  to  give  to  the  student  some  idea  of  the 
construction  of  the  instruments  usually  found  in  an  astronomical 
observatory.  In  mounting  these  telescopes  for  scientific  use, 
the  greatest  pains  must  be  taken  to  secure  a  firm  foundation ; 
such  is  the  delicacy  of  these  instruments,  that  nothing  short  of 
the  most  solid  and  isolated  foundation,  will  render  their  results 
reliable.  At  the  Cincinnati  Observatory,  large  piers  of  grouted 
masonry  are  founded  on  the  rock,  and  carried  up  to  a  hight 
suitable  to  receive  the  stone  columns  on  which  the  telescopes 
are  fixed.  These  piers  are  entirely  isolated  from  the  building 
and  are  secured  from  any  external  action. 


324  GEOGRAPHY  OF  THE  HEAVENS. 


CHAPTEE  XIV. 

QUESTIONS  ON  THE  MAPS;  TABLES,  ETC. 

IT  has  been  thought  unnecessary,  as  it  is  quite  impracticable, 
to  present  a  full  set  of  questions  on  each  of  the  constellations, 
and  other  topics  treated  in  this  volume.  This  would  have  in- 
creased the  size  of  the  volume  to  nearly  twice  its  present  dimen- 
sions, without  increasing  its  value.  Every  judicious  teacher 
will  pursue  his  own  plan  of  communicating  instruction,  and  will 
never  confine  himself  or  his  pupils  to  a  set  of  stereotyped 
questions. 

We  present,  therefore,  as  a  mere  specimen  of  the  kind  of  exa- 
mination which  we  deem  important,  a  series  of  Questions  on  the 
Constellation  Cygnus,  Map  No.  20. 

Is  the  Swan  a  northern  or  southern  constellation]  In  what 
declination  is  its  southern  limit  ?  How  far  north  does  it  extend  ? 
Between  what  hours  of  R.  A.  is  it  included  ?  How  is  it  bounded 
on  the  south,  east,  north,  west?  How  is  it  situated,  with  refe- 
rence to  a.  Lyrae?  How  may  the  constellation  be  recognized  in 
the  heavens  ?  What  stars  constitute  the  longer  piece  of  the 
Cross  ?  What  stars  the  shorter  piece  ?  What  is  the  name  and 
magnitude  of  *  Cygni?  How  many  stars  of  the  third  magni- 
tude are  contained  in  the  Swan,  and  their  letter  names?  Where 
are  ^  £,  and  «  situated  ?  Where  is  ft  situated  ?  Where  are  ef, 
6,  and  *  found  ?  What  are  some  of  the  principal  double  stars  ? 
What  are  the  magnitudes  and  colors  of  the  components  of  $  Cyg- 
ni?  What  remarkable  fact  in  the  history  of  the  components  of 
$  Cygni  ?  What  their  distance,  and  probable  period  of  revolu- 
tion ?  Give  some  account  of  the  discovery  of  the  parallax  of  61 
Cygni.  What  is  the  distance  of  this  set  from  our  system  ? 
What  their  period  of  revolution  ?  What  the  sum  of  the  masses 
of  these  stars,  compared  with  the  sun's  mass  ?  What  is  the 
distance  and  magnitude  of  the  components  of  61  Cygni  ?  Why 
was  it  selected,  by  Bessel,  for  his  researches  for  parallax? 
How  does  its  swift  proper  motion  accord  with  Madler's  theory 
of  a  central  sun  ? 

What  remarkable  nebulae  are  found  in  the  constellation  ?  What 
curious  phenomena  have  been  remarked  in  the  planetary  nebulae 


QUESTIONS  ON  THE  MAPS,  ETC. 


325 


near  <f  Cygni  ?  What  may  be  said  with  regard  to  the  magnitude 
and  distance  of  these  objects  ?  Are  they  situated  in  the  region 
of  the  fixed  stars  1  How  should  the  chart  or  map  be  held,  to 
make  its  stars  correspond  to  those  in  the  heavens  ? 


TABLES. 


PLACES  OF  THE  PLANETS  IST  JANUARY,  1849. 

FROM  these  places,  and  the  elements  of  the  planets  given  in 
this  work,  the  approximate  positions  of  the  planets  may  be 
readily  computed,  so  as  to  find  them  at  any  time. 


Names. 

Mercury, 

Venus, 

Mars, 

Vesta, 

Juno, 

Pallas, 

Ceres, 

Jupiter, 

Saturn, 

Uranus, 


TABLE  I. 

Apparent  R.  A. 
18h.  29m.  23s. 


21      33 
17      03 
0 


53 
24 
12      00 


5  16  30 
16  33  18 
16  39  30 


9      37 
23      26 


07 
33 
08      40 


Apparent  Dec. 

S.  24°  46'  01' 

S.  16     22  28 

S.  23     05  40 

S.     6     24  00 

S.     0     19  00 

N.    3     10  00 

S.  19     18  00 

N.  15     10  03 

S.     5     57  12 

N.    6     37  56 


2D 


326 


GEOGRAPHY  OF  THE  HEAVENS. 


lADJjJ^    11. 

I'o  change  degrees,  minutes,  and 
seconds  of  the  equator,  or  of 
right  ascension,  into  hours,  mi- 
nutes, and  seconds,  of  sidereal 
time. 

LADLtCj  111. 

To  change  hours,  minutes,  and  se- 
conds, of  sidereal  time,  into  degrees, 
minutes,  and  seconds,  of  the  equa- 
tor, or  right  ascension. 

Deg. 

Mi. 
Sec. 

1 

2 
3 

•4 
5 

H.  M. 
1YI.  S. 
S.  Th. 

Deg. 
Min. 
Sec. 

K.  M. 
M.S. 
S.Th 

4 

V 

1 

a 

w 

S    1 

11 

33 

1 
I 

Min.  D.  M. 
Sec.    M.  S. 
Th.     S  Th. 

Min. 

Sue. 
T)i. 

D.  M. 

M.  S. 
S.  Th. 

0     4 
0     8 
0  12 
0  16 
0  20 

31 
32 
33 
34 
35 

2     4 
2     8 
2  12 
2   16 
2  20 

70 
80 
90 
100 
110 

4  40 
5  20 
6     0 
6  40 
7  20 

1 
2 
3 
4 
5 

15 
30 
45 
60 
75 

1    0  15 
2    0  30 
3    0  45 
410 
5  ll   15 

31 
32 
33 
34 
35 

7  43 

8     0 
8  15 
8  30 
8  45 

6 
7 
8 
9 
10 

11 
12 
13 
14 
15 

0  24 
0  28 
0  32 
0  36 
0  40 

36 
37 

38 
39 
40 

2  24 
2  28 
2  32 
2  36 
2  40 

120 
130 
140 
150 
160 

170 
180 
190 
200 
210 

8     0 
8  40 
9  20 
10     0 
10  40 

6 

7 
8 
9 
10 

90 
105 
120 
135 
150 

6 

ri 

8 

9 
10 

1  30 
1  45 
2     0 
2  15 
2  30 

36 
37 
38 
39 
40 

9     0 
9  15 
9  30 
9  4,3 
10     0 

0  44 
0  48 
0  52 
0  56 
1     0 

41 
42 

43 
44 
45 

2  44 

2  48 
2  52 
2  56 
3     0 

11  20 
12     0 
12  40 
13  20 
14     0 

11 

12 
13 
14 
15 

165 

180 
195 
210 
225 

H 
12 
13 
14 
15 

2  45 
3     0 
3  15 
3  30 
3  45 

41 

42 
43 
44 
45 

10   15 

10  30 
10  45 
11     0 
11   15 

11  30 
11  45 
12     0 
12   15 
12  30 

16 
17 
18 
19 
20 

4 
8 
12 
16 
20 

46 

47 
48 
49 
50 

3     4 
3     8 
3  12 

3   16 
3  20 

220 
230 
240 
250 
260 

14  40 
15  20 
16     0 
16  40 
17  20 

16 
17 
18 
19 
20 

2401   16 
255J    17 
270;    18 
285    19 
300    20 

4     0 
4  15 
4  30 
4  45 
5     0 

46 

47 
48 
49 
50 

21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

24 

28 
32 
36 
40 

51 
52 
53 
54 
55 

3  24 
3  28 
3  32 
3  36 
3  40 

270 
280 
290 
300 
310 

18     0 
18  40 
19  20 
20     0 
20  40 

21 
22 
23 
24 
25 

315 
330 
345 
360 
375 

21 
22 
23 
24 
25 

26 
27 
28 
29 
30 

5  15 
5  30 
5  45 
6     0 
6  15 

6  30 
6  45 

7     0 
7  15 
7  30 

51 
52 
53 
54 
55 

56 
57 
58 
59 
60  i 

12  45 
13     0 
13  15 
13  30 
13  45 

14     0 
14  15 
14  30 
14  45 
15     0 

44 
48 
52 
56 
2     0 

56 
57 
58 
59 
60 

3  44 

3  48 
3*52 
3  56 
4     0 

32021  20 
330  22     0 
340  22  40 
350  23  20 
360  24     0 

26 

27 
28 
29 
30 

390 
405 
420 
435 
450 

LATITUDE,  ETC.,  OF  PLACES  IN  UNITED  STATES.    32' 


TABLE  IV. 

Showing  the  Latitude  and  Longitude  of  some  of  the  principal  Places  in 
the  United  States,  &c.,  with  their  Distances  from  the  City  of  Wash- 
ington. 

Tke  Longitudes  are  reckoned  from  Greenwich. 

The  Capitals  (Seats  of  Government}  of  the  States  and  Territories  are 
designated  by  Italic  Letters. 


•  N.  Y 
•  D.C. 
Md 

Latitude 
North. 

Longitud 
iu  degrees 

e,  West. 
in  time. 

Dist.frora 
Wash'n. 

miles. 
376 
6 
37 
339 
580 
595 
38 
661 
466 
370 
629 
432 
409 
227 
568 
376 
431 
467 
336 
507 
544 
433 
497 
500 
396 
474 
422 
526 
1278 
432 
114 
490 
80 
778 
284 
474 
5^1 
56 

43 
482 
462 
396 
68 
936 
593 
110 

o     /     n 
42  39    3 
38  49 
39    0 
42  55 
33  28 
44  18  43 
•>9  17  13 
44  47  50 
41  42    9 
42  59 
<2  25 
4-2  21  15 
41  39  58 
40  41  50 
43  53    0 
42  53 
42  22  15 
34  T7 
42  54 
42    2  16 
32  47    0 
42  22 
39     6 
33  57 
39  47 
43  12  29 
42  16 
42  24 
30    3 
42  19  15 
39  10 
43  13 
38  46  10 
44  54 
36    0 
42  58 
38  14 
3834 
46    3 
39  24 
33  21 
42  36 
42  37 
39  37 
44  39  20 
44  17 
40  16 
41    4fi 

0       1       II 

73  44  49 
77    4 
76  43 
76  28 
PI  54 
69  50 
76  37  50 
68  47 
70  16 
78  13 
80  41 
71     4    9 
71  19 
73  59  30 
69  55    1 
78  55 
71     7  25 
80  30 
77  17 
70    4 
80    0  52 
71    333 
84  22 
81    7 
83    3 
71  29 
71  11 
82  5s 
91    2 
71    4  15 
75  30 
70  54 
76    8 
66  56 
77    7 
70  55 
84  40 
77  38 
66  45 
77  18 
79  17 
70  40 
72  36 
77  35 
63  36  40 
69  50 
76  50 
TO  ^n 

h.  m.  s. 
4  54  59  3 
5    8  16 
5    6  52 
5    5  52 
5  27  36 
4  39  20 
5    6  31.3 
4  35    8 
4  41    4 
5  12  52 
5  22  44 
4  44  1(5.6 
4  45  36 
4>55  58 
4  39  40.1 
5  15  40 
4  44  29.7 
5  22  12 
598 
4  40  16 
5  20    3.5 
4  44  142 
5  37  26 
5  24  28 
5  32  12 
4  55  56 
4  44  44 

5  31  52 
648 
4  44  17 
520 
4  43  36 
5    4  32 
4  27  44 

N.  Y. 
Ga. 
•  Me. 

Md. 
Me. 

Mass. 

N.Y. 

s  c 

A                 ' 

Baltimore  (Battle  Monument). 
Bangor  (Court  House),  
Barnstable  (Old  Court  House), 

•Mass. 
R.  I. 
N.Y. 
Me. 
•  N.Y. 
Mass. 
S.  C. 
•  N.Y. 
Mass 
S.  C. 
Mass. 
Ohio. 
S.  C. 
Ohio. 
N.  H. 
Mass. 
Mif>h 

Brooklyn  (Navy  Yard).  

Buffalo  

Cambridge  (Harvard  Hall),-.. 

Cape  Cod  (Light  House)   

Charlestown  (Na°vy'Yard),-  •• 

£,1I^m!\atL' 

r  i     h   ' 

Ded  ham  (  Court  House  ),  

•  La. 
Mass. 
•  Del. 

•N.  H. 
•Md 

Dorchester  (  Asi.  Observatory), 

Me. 
N.  C. 
N.  H. 
Ky. 
Va. 

4  43  40 
5  38  40 
5  10  32 
4  27    0 
5    9  12 
5  17    « 
4  42  40 
4  50  24 
5  10  20 
4  14  27 
4  39  30 
5    7  20 

A    K1    on 

Fredericksburg,  :  .  .  . 

Md. 
S.  C. 
Mass. 
Mass. 
Md. 
N.  S. 
Me. 
Pa. 

Halifax    -  ••  •  

Hallowell   

Hartford.  •• 

328 


GEOGRAPHY  OF  THE  HEAVENS. 


NY 

Latitude 
North. 

Longitud 
in  degrees. 

;,  West, 
in  time. 

Dist.  from 
Wash'n. 

Q      1       II 

42  14 

34  36 
39  55 
32  23 
38  36 
43  25 
44    8 
35  59 
40    2  30 
38    6 
34  40 
43  11 
38    3 
42  38  45 
37  36 
42  28 
42  30 
41  34 
33    7 
30  40 
44  17 
41  32  58 
45  31 
41  16  32 
36    9  30 
31  34 
40  45 
41  38    7 
35  20 
41  31 
42  48  29 
39  40 
41  17  58 
41  22 
29  57  45 
41  29 
40  42  40 
36  50  50 
42  18  55 
41  33 
30  28 
37  13  54 
39  56  59 
40  32 
42  26  59 
44  42 
41  57  12 
43  39  26 
43    4  54 
41  41 
40  22 
41  49  25 
46  47  17 
35  47 
37  32  17 
43    8  17 
24  50 
43  55 
43  31 
29  48  30 
3£  36 

0       /       // 

73  46 
86  57 
80     5 
90    8 
92    8 
70    32 
76  40 
83  54 
76  20  33 
84  18 
92  12 
78  46 
85  30 
71  18  45 
79  22 
70  57 
70  52 
72  39 
83  20 
S811 
7236 
70    1  31 
73  35 
70    7  42 
86  49    3 
91  24  42 
74  10 
70  56    0 
77    5 
74    1 
70  52    0 
75  33 
72  57  46 
72    9 
90    6  49 
71  21  14 
74    1    8 
76  18  47 
72  40 
72    7 
87  12 
77  20 
75  10  59 
30    8 
73  17  30 
73  26 
70  42  30 
70  20  30 
70  45 
73  55 
74  35 
71  25  56 
70  56  31 
78  48 
77  26  28 
77  51 
81   15 
75  57 
70  26 
81  35 
89  3fi 

h.  m.  s. 
4  55    4 
5  47  48 
5  44  20 
6    0  32 
6    8  32 
4  42    8 
5    6  40 
5  35  36 
5    5  22.2 
5  37  12 
6    848 
5  15    4 
5  42    0 
4  45  15 
5  1728 
4  43  48 
4  43  28 
4  50  36 
5  33  20 
5  52  44 
4  50  24 
4  40    6.1 
4  54  20 
4  40  30.8 
5  47  16.2 
6    5  38.8 
4  56  40 
4  43  44 
5    8  20 
4  56    4 
4  4328 
528 
4  51  51.1 
4  48  36 
6    0  27  .3 
4  45  24.9 
4  56    4.5 
5    5  15.1 
4  50  40 
4  4828 
5  48  48 
5    9  20 
5    0  43.9 
5  20  32 
4  53  10 
4  53  44 
4  42  50 
4  41  22 
4  43    0 
4  55  40 
4  5820 
4  45  43  7 
4  43  46.1 
5  15  12 
5    9  49.9 
5  11  24 
5  25    0 
5    3  48 
4  41  44 
5  26  20 
*>  f»  24 

miles. 
345 
726 
573 
1035 
980 
518 
456 
516 
109 
534 
1068 
403 
590 
439 
198 
441 
450 
325 
642 
1033 
524 
500 
6U1 
500 
714 
1146 
215 
4-29 
337 
282 
466 
103 
301 
354 
1203 
403 
226 
217 
376 
302 
1050 
144 
136 
223 
3SO 
539 
439 
542 
491 
301 
177 
394 
781 
286 
122 
361 

407 
528 
841 

856 

•  Ala 

ri  urns  vi  lie, 

M'ni 

•  M'uri 

Jefferson, 

Me 

•  U  C 

Jvnoxviiie, 

•  Pa 

Lancaster* 

Tfv 

Arlf 

-N.  Y. 
•  Ky 

Lowell  (St.  Ann's  Church),  ••• 

•Mass. 
•Va 

ij>  ncnuurgn, 

Mas« 

Mas« 

Milledseville         •       

•  Ga 

»  I-. 

•Vt 

•  Mass 

ivionomoy  romt  ijigrit, 

T    P 

Montreal, 

Mass. 

Nashville  

M'pi 

Newark  

•N  J 

New  Bedford  (Mariners'  Ch.), 

•  Mass 
Np 

•  N  Y 

Newburyport  (2d  Pres.  Ch.),-  • 

•  Mass. 
•  Ttel 

•  Conn 

i>ew  ijoncion. 

La 

•  R  1 

New  York  (City  Hall)  

.  TV     V 

Norfolk  (Farmer's  Bank).  Va. 
Northampton  (Mansion  House),  Mass. 

iNorwicn, 

Fla 

rensacola, 

•  Va 

Philadelphia  (Independ.  Hall), 

•Pa. 
Pa 

Pittsfield  (1st.  Cong.  Church),  • 

•  Mass. 
•N   Y 

Plymouth  (Court  House),  

•  Mass. 
•  Me 

Portsmouth  (Court  House),  •  •  • 

•  N.  H. 
N  Y 

rougnKeepsie, 

TV   T 

•  R  I 

Lp 

N.C. 
•  Va. 
Nif 

Sable  (Cape)   

•  Fla. 
•N  Y 

*>aco  '    

Me 

•Fla 

St.  Louis.  

•  M'ri. 

LATITUDE,  ETC.,  OF  PLACES  IN  UNITED  STATES.    329 


Salem  (E.  I.  M.  Hall), Mass.  4231  19 

Savannah, Ga.  32    2 

Schenectady, N.Y.  42  48 

Springfield  (Court  House), Mass.  42    5  58 

Tallahassee, Fla.  30  28 

Taunlon  (Court  House),  Mass.  41  54    9 

Toronto  (York), U.  C.  43  33 

Trenton, N.J.  40  14 

Troy.   N.Y.  4244 

Tuscaloosa, Ala  33  12 

University  of  Virginia, Va.  38    2    3 

Utica  (Dutch  Church). N.Y.  43    649 

Vandalia, • 111.  38  50 

Vevay, ...Ind.  38  46 

Vincennes, Ind.  38  43 

WASHINGTON  (Capitol), D-  C.  38  52  54 

Washington, M'pi.  31  36 

Wheeling. Va.  40    7 

Wilmington. Del.  39  41 

Wilmington, N.  C.  34  11 

Worcester  (Ant.  Hall), Mass.  42  16    9 

York.    Me.  4310 

York, Pa.  39  58 


Latitude 
Nortn. 


Longitude,  West, 
in  degrees,  in  time. 


o  /  n 

70  54 
81  3 

73  55 

72  36 
84  36 

71  50 

79  20 

74  39 

73  40 
87  42 
78  31  29 

75  13 
89  2 
84  59 
87  25 

77  1  48 
91  20 

80  42 

75  28 

78  10 

71  49  0 
70  40 

76  40 


h  m.  s. 

4  43  36 

5  24  12 
55  40 
50  24 


o  38  24 

4  44  20 

5  17  20 
4  58  36 

4  54  40 

5  50  48 

5  14  5.9 

0  52 
5  56  8 
5  39  56 

5  49  40 

8  7.2 

6  5  20 
5  22  48 

1  52 
5  12  40 
4  47  16 
4  42  40 

3  40 


Dist.  Iroin 
Wash'n. 


miles. 
446 
662 
391 
3.)7 
896 
415 
500 
166 
383 
858 
124 
383 
781 
556 

1693 

146 
264 
108 
416 
394 
500 


2D2 


HDNTINGTON  AND  SAVAGE, 

216  PEARL-STREET,  NEW  YORK, 

PUBLISH    THE    FOLLOWING 

VALUABLE  SCHOOL  BOOKS, 

To  which  they  very  respectfully  solicit  the  attention  of  County  and  Town 
Superintendents,  Trustees,  School  Committees,  Teachers,  and  others  inter- 
ested in  the  cause  of  education. 


AN  ELEMENTARY  ASTRONOMY, 

For  Academies  and  Schools.      Illustrated  by  numerous  original  colored 
diagrams.     Adapted  to  use  with  or  without  the  author's  Large  Maps. 

BY  H.  MATTISON. 

Fifth  Edition,  with  Questions  and  a  Glossary. 

This  is  one  of  the  most  comprehensive  and  splendidly  illustrated  works 
on  Astronomy  that  has  ever  been  published  in  the  United  States.  Its  plan  is 
eminently  original  and  philosophical.  It  is  confined  to  the  facts  of  the  sci- 
ence, or  the  results  that  have  been  reached  during  the  lapse  of  ages,  without 
delineating  its  Mythological  history,  or  tracing  the  processes  by  which  these 
facts  have  been  ascertained,  either  by  the  use  of  instruments,  or  by  mathe- 
matical calculations.  It  embodies  all  the  late  discoveries,  and  is  equally 
adapted  to  private  learners,  the  library,  and  the  schoolroom,  as  it  is  com- 
plete in  itself,  independent  of  the  large  charts.  As  a  book  of  reference  it  is 
invaluable.  To  this  may  be  added  its  perfect  adaptation  to  use  with  the  large 
Maps,  (of  which  the  illustrations  in  the  book  are  exact  copies  in  miniature,) 
so  that  the  learner  having  the  Maps,  has  on  a  large  scale  the  same  diagrams 
by  which  to  illustrate  the  lesson  at  the  recitation,  that  haveJ>een  previously 
studied  by  the  pupil  in  the  text-book.  To  say  nothing  of  .Me  recommenda- 
tions that  follow,  the  sale  of  ten  thousand  copies  of  this  work,  in  a  little  over  a 
year,  is  a  sufficient  proof  of  its  popularity  and  intrinsic  value. 

ASTRONOMICAL  MAPS, 

Adapted  to  use  with  the  "  ELEMENTARY  ASTRONOMY,"  and  designed  to  illus- 
trate the  Mechanism  of  the  Heavens.  For  the  use  of  Public  Lecturers, 
Private  Learners,  Academies,  and  Schools. 

BY  H.  MATTISON. 

This  series  consists  of  Sixteen  Maps,  or  Celestial  Charts,  each  38  by  44 
inches,  representing  the  various  appearances  of  the  Heavenly  Bodies— the 
Sun,  Moon,  Planets,  Comets,  and  Fixed  Stars— and  illustrating  the  laws 
which  govern  them  in  their  motions,  the  philosophy  of  Tides,  Eclipses,  and 
Transits,  and  indeed  all  the  most  interesting  and  wonderful  phenomena  ot 
the  Mechanism  of  the  Heavens.  The  sixteen  Maps  cover  an  area  of  nearly 
200  square  feet.  They  are  printed  upon  a  black  ground,  answering  to  the 
natural  appearance  of  the  heavens  in  the  night,  and  are  beautifully  colored 
and  mounted  upon  slats  and  rollers.  They  are  beyond  comparison  the  most 
splendid  and  complete  series  of  scientific  charts  ever  published  in  this  coun- 
try. They  are  not  only  invaluable  for  Seminaries,  Academies,  and  the  higher 
institutions  of  learning,  but  at  the  same  time  are  admirably  adapted  to  pop- 
ular use  in  Common  Schools.  One  thousand  sets  of  this  work  have  already 
been  sold  and  gone  into  use  in  different  parts  of  the  country  ;  and  the  una- 
nimity and  cordiality  with  which  they  are  commended  by  all  who  have  used 
or  examined  them,  is  truly  gratifying  to  the  publishers.  (See  following  page.) 

MAPS,  per  set,  in  case,  with  cloth  backs, $20  00 

"          "           "          on  strong  paper,  without  cloth  backs,      15  00 
Books  per  copy, 50 

93-  Each  Set  of  Maps  is  nicely  packed  in  a  Wooden  Case,  and  can  b« 
sent  to  order  with  perfect  safety  to  any  part  of  the  United  States  or  Canada 


Huntington  fy  Savage's  Publications. 


The    attention    of   Superintendents   of    Schools,    Trustees,    and 
Teachers,  is  respectfully  invited  to  the  following 

RECOMMENDATIONS 

Of  the   «« Elementary  Astronomy,"    and   "Astronomical 
Maps." 


Having  examined,  and  several  of  us  used,  the  ELEMENTARY  AS- 
TRONOMY and  ASTRONOMICAL  MAPS,  by  H.  Mattison,  we  are  prepared 
to  say,  that  in  our  opinion,  they  are  better  adapted  to  the  purposes 
of  elementary  instruction  in  Astronomy,  than  any  other  work  or  ap- 
paratus now  before  the  public.  We  would  therefore  cordially  re- 
commend their  introduction  into  all  schools  where  this  sublime  science 
is  taught. 

EDWARD  COOPER,  Sec'y  of  Teachers'  Association,  state  N.  Y. 

ALBERT  D.  WRIGHT,  Principal  Normal  Inst.,  Brooklyn,  N.  Y. 

JAS.  L.  McELLIGOTT,  Prin.  Col.  School,  N.  Y.  city. 

JAS.  R.  BOYD,  Prin.  Jefferson  co.  Inst.,  Watertown,  N.  Y. 

R.  K.  S^TFORD,  Teacher  Natural  Science,  Middlebury  Academy, 

Wyoming,  N.  Y. 

N.  BRITTAN,  Principal  of  Union  School,  Lyons,  N.  Y. 
R.  F.  HICKS,  County  Supt.,  Livingston  co.,  N.  Y. 
ALONZO  BEEBE,  County  Supt.,  Ontario  co.,  N.  Y. 
HENRY  GILLAM,  former  teacher  of  Math.  Cayuga  Academy,  N.  Y 
B.  R.  McALPINE,  Supt.  of  Public  Schools,  Rochester,  N.  Y. 
ELLERY  S.  TREAT,  Prin.  Pub.  School  No.  1,  Rochester,  N.  Y. 
WM.  BARNES,  "  "  «      5, 

A.  F.  HALL,  "  "  »«      7,  " 

REUBEN  JOHNSON,      ••  "  "      9,  »        ?/t  >• 

DANIEL  HALLOCK,       "  "  "    11, 

A.  S.  GREGORY,  "  ««  "     14,  " 

H.  G.  WINSLOW,  Prin.  Union  School,  Mount  Morris,  N.  Y. 
S.  P.  BARKER,  Prin.  Public  School  No.  10,  Brockport,  N.  Y. 
G.  L.  FARNAM,  Prin.  Public  School  No.  3,  Watertown,  N.  Y. 
G.  R.  JACKSON,  Teacher,  Oswego,  N.  Y. 
1.  PATTERSON,  Prin.  Public  School  No.  4,  N.  Y.  city. 
JULIA  B.  CLARKE,  Teacher  of  Public  School  No.  1,  Oswego,  N.  Y. 


From  PROF.  MITCHEL,  Director  of  the  Cincinnati  Observatory. 

In  a  note  to  the  publishers,  Prof.  M.  says : 

"  Your  series  of  Maps  are  hung  up  in  the  public  reception-room  of 
the  observatory.  I  am  much  pleased  with  your  plan  of  speaking  to 
the  eye ;  and  am  confident  that  these  maps  will  soon  find  their  way 
i»u)  every  well-conducted  school." 


Huntington  8f  Savage's  Publications. 


From  PROF.  CASWELL,  of  Brown  University,  and  N.  BISHOP,  Esa., 
Superintendent  of  Public  Schools  in  Providence,  R.  I. 

From  a  brief  examination  of  Mr.  Mattison's  "  Elementary  Astron- 
omy," and  the  accompanying  Maps,  we  have  formed  a  favorable 
opinion  of  their  utility  to  pupils  in  that  branch  of  study,  and  have 
recommended  their  introduction  into  the  High  School  of  the  city  of 
Providence. 

March  11,  1847. 


From  REV.  RICHARD  S.  RUST,  Commissioner  of  Public  Schools  for 
the  State  of  New  Hampshire. 

1  have  examined  with  great  pleasure,  Mr.  Mattison's  Elementary 
Astronomy,  and  Astronomical  Maps,  and  I  think  them  admirably 
adapted  to  arrest  the  attention  of  the  young,  and  to  impart  thorough 
and  practical  knowledge  in  the  sublime  study  of  Astronomy. 

I  admire  the  arrangement  and  classification'of  the  Astronomy.  It 
explains  and  illustrates  one  thing  at  a  time,  in  a  manner  so  clear  and 
interesting,  that  it  cannot  fail  of  entertaining  and  improving  the  student 

In  view  of  the  excellencies  of  the  Elementary  Astronomy,  and 
Maps,  I  most  cheerfully  commend  them  to  an  intelligent  public, 
hoping  that  they  will  meet  with  all  that  success  which  their  merits  so 
richly  deserve. 

Mar.  18,  1847. 


From  REV.  SAMUEL  H.  Cox,  D.  D.,  of  Brooklyn,  N.  Y. 

These  Maps,  mathematical  and  optical,  illustrate  the  noblest  parts 
of  that  incomparable  science  ;  they  are  accompanied  by  an  explana- 
tory volume,  adapted  to  them,  lucidly  arranged,  all  forming,  I  think, 
an  apparatus  for  the  learner  and  the  scholar,  of  rare  excellence  and 
enduring  usefulness.  Results  and  processes  are  there  combined,  re- 
duced to  system,  and  digested  consecutively  in  happy  order ;  compe- 
tent to  instruct  the  merchant,  the  mechanic,  the  farmer,  the  inquisi- 
tive youth,  the  gentleman  of  leisure,  and  all  others  who  aspire  after 
sublime  knowledge,  and  are  willing  sometimes  to  look  at  the  heavens. 
Ladies  who  value  true  knowledge,  and  who  have  learned  how  to 
think — and  there  are  some  of  this  description — will  prize  such  instru- 
mental helps  to  the  acquisition  of  sound  and  rich  information  in  As- 
tronomy. As  a  work  of  reference,  a  thesaurus  of  knowledge,  a 
profitable  amusement,  or  an  ornamental  pursuit,  it  would  greatly 
honor  as  well  as  happily  form  their  mental  character,  and  subordinate 
the  very  gems  of  heaven  to  their  proper  decoration  as  intellectual  and 
immortal  beings.  I  need  not  add  it  is  very  valuable  for  schools,  and 
deserves  the  patronage  of  our  countrymen,  as  a  native  production.  1 
sincerely  desire,  as  well  as  anticipate  its  success. 

May  G,  1847. 


16  Huntington  fy  Savage's  Publications. 

THE 

GEOGRAPHY  OF  THE  HEAVENS, 

AND  CLASS-BOOK  OF  ASTRONOMY. 

1  vol.  18mo. 
Accompanied  by  a  Celestial  Atlas,  imperial  4to.,  neatly  colored. 

in  admirable  work  to  follow  the  "  ELEMENTARY  ASTRONOMY"  AND  "  AS- 
TRONOMICAL MAPS."  The  two  works  together  present  a  more  thorough 
embodiment  of  the  science  than  any  others  of  the  same  compass,  in  the 
country. 

CONTENTS   OF   THE   ATLAS. 

1.  Plan  exhibiting  the  relative  Magnitudes,  Distances,  and  Position  of  the 

different  Bodies  which  compose  the  Solar  System. 

2.  The  Visible  Heavens  in  January,  February,  and  March. 

3.  The  Visible  Heavens  in  October,  November,  and  December. 

4.  The  Visible  Heavens  in  July,  August,  and  September. 

5.  The  Visible  Heavens  in  April,  May,  and  June. 

6.  The  Visible  Heavens  in  the  South  Polar  Regions,  for  each  month  in 

the  year. 

7.  The  Visible  Heavens  in  the  North  Polar  Regions,  for  each  month  in 

the  year. 

8.  Planisphere  of  the  Whole  Heavens,  on  Mercator's  Projection. 

BY  E.  A.  BURRITT,  A.  M. 

With  an  Introduction  by  THOMAS  DICK,  LL.  D.,  Author  of  the  "  Christian 
Philosopher,"  written  expressly  for  this  work. 

A  variety  of  interesting  facts  and  observations,  embracing  the  latest  im- 
provements in  the  science,  were  derived  directly  from  the  French  and  Eng- 
lish Observatories,  expressly  for  this  Class-Book.  and  are  not  contained  in 
any  other.  It  is  now  coming  generally  into  use  y\  our  principal  Seminaries, 
and  is  recommended  to  schools  in  general  by  members  of  the  Board  of  Ex- 
amination of  Yale  College,  as  a  work  more  needed,  and  which,  it  is  be- 
lieved, will  be  more  useful  than  any  other  introduced  into  our  "  Institutions 
of  Learning,  for  a  number  of  years." 

This  book,  as  its  title  imports,  is  designed  to  be  to  the  starry  heavens 
what  geography  is  to  the  earth.  Such  a  Class-Book  has  long  been  needed. 
Hitherto,  the  science  of  the  stars  has  been  but  very  superficially  studied  in 
our  schools,  for  want  of  proper  helps.  They  have  continued  to  gaze  upon 
the  visible  heavens  without  comprehending  what  they  saw.  They  have 
cast  a  vacant  eye  upon  the  splendid  pages  of  that  vast  volume  which  the 
night  unfolds,  as  children  amuse  themselves  with  a  book  which  they  are 
unable  to  read.  They  have  caught,  here  and  there,  as  it  were,  a  capital 
letter,  or  a  picture,  but  they  have  failed  to  distinguish  those  smaller  charac- 
ters, on  which  the  sense  of  tbe  whole  depends.  Both  teachers  and  pupils 
have  found  that  Class-Books  and  Maps  are  as  indispensable  to  this  depart- 
ment of  knowledge,  as  to  that  of  Geography  ;  and  that  an  artificial  globe  is 
just  as  poor  a  substitute  in  one  case  as  in  the  other.  Instead  of  the  globe, 
and  a  few  balls  strung  upon  wires,  Mr.  Burritt's  book  and  Atlas  introduces 
the  pupil  at  once  to  the  Grand  Orrery  of  the  Heavens,  and  makes  him 
acquainted  with  the  names  and  positions  of  the  bodies  which  compose  it. 
He  learns  to  locate  and  to  classify  his  astronomical  knowledge  as  he  does  his 
geographical ;  and  experience  has  proved  that  a  child  of  ten  years  will  trace 
out  all  the  constellations  that  are  visible  in  the  heavens,  and  name  the 
principal  stars  in  each,  as  readily  as  he  will  learn  the  boundaries  of  the 
States  from  a  map,  and  name  the  cities  they  contain. 


Huntington  if*  Savage's  Publications.  17 

A  NATIONAL  GEOGRAPHY  FOR  SCHOOLS, 

Illustrated  by  220  Engravings  and  60  Stylographic  Maps ;  with  a  colored 
GLOBE  MAP,  ON  A  NEW  PLAN. 

O  ne  vol.  quarto. 

New  and  improved  edition. 

BY  S.  G.  GOODRICH,  Author  of  Peter  Parley's  Tales. 

This  work  is  designed  as  a  school-book— &  manual  for  teaching;  and  nothing 
in  the  w  ork  is  allowed  to  interfere  with  this  design.  At  the  same  time,  from 
the  arrangement  adopted,  it  will  be  found  to  contain  a  great  quantity  o( 
matter  which  will  render  it  a  convenient  family  book  for  reference.  Its 
utility,  in  this  respect,  will  be  enhanced  by  the  index  at  the  close  of  the 
volume. 

Simplicity,  perspicuity,  and  convenience  have  been  carefully  studied  in  the 
arrangement  of  the  whole  work.  Thus  the  typography,  especially  that 
which  contains  the  leading  ideas  of  each  lesson,  is  clear  and  conspicuous  ; 
the  lettering  of  the  maps  is  peculiarly  full  and  distinct ;  the  whole  view  of 
each  country  is  brought  together,  so  as  not  to  embarrass  the  reader  by  a 
reference  to  separate  pages,  or  separate  tables  ;  distinct  maps  of  the  prin 
cipal  countries  are  given,  and  care  has  been  taken  not  to  fill  them  with  un 
important  names,  which  may  bewilder  the  student,  and  render  all  his  ac- 
quisitions obscure  and  imperfect.  Too  many  of  the  popular  school-books 
on  this  subject  are  made  to  compass  two  objects ;  to  combine  a  universal 
geography  and  a  school  geography  in  one.  Both  objects  are  not,  therefore, 
well  attained,  for  while  there  is  not  enough  for  the  former,  there  is  too 
much  for  the  latter :  the  consequence  is  inconvenience  and  embarrassment 
to  the  teacher — increased  study  and  labor  to  the  pupil,  while  he  is  im- 
perfectly instructed,  if  not  actually  injured  in  his  habits  of  study.  The 
maps  and  text  of  this  work  contain  quite  as  much  of  detail  as  the  pupil  can 
remember.  The  design  has  been  to  embrace  just  so  much,  that,  if  well 
studied,  the  pupil  will  carry  in  his  mind  clear  and  distinct  images  of  the 
forms  of  countries,  courses  of  rivers,  location  of  towns,  cities,  &c.,  so  that 
every  country,  with  its  leading  features,  can  be  and  will  be  permanently 
mapped  on  his  mind. 

In  respect  to  maps  a  new  and  useful  device  has  been  adopted,  which  we 
entitle  a  Globe  Map.  This,  of  necessity  is  separate  from  the  pages  referring 
to  it,  but  its  great  utility  and  convenience,  in  the  way  it  is  to  be  used,  can- 
not fail  to  strike  every  practical  teacher.  It  has  a  handle,  and  with  a  model 
of  the  globe  in  his  hand,  the  pupil  is  taught  the  various  names  given  to  the 
divisions  of  land  and  water,  the  shapes  of  oceans  and  continents,  and  the 
relative  positions  of  countries  and  places  upon  the  face  of  the  earth. 
It  is,  in  short,  a  substitute  for  an  artificial  globe,  with  the  advantage  of  being 
tasily  handled*  and  constantly  before  the  eye,  during  the  early  stages  of 
the  study. 

As  a  means  of  rendering  the  progress  of  the  pupil  at  once  agreeable  and 
effective,  the  author  has  endeavored  to  invest  the  subject  with  every  de- 
gree of  interest  of  which  it  is  capable.  He  has  sought  to  keep  the  attention 
alive  by  vivid  descriptions  ;  and,  in  order  to  convey  accurate  impressions  of 
visible  objects,  he  has  introduced  a  larger  number  of  illustrative  engravings 
than  have  ever  appeared  in  a  similar  treatise.  Every  one  knows  that  mere 
words  are  incapable  of  conveying  correct  and  distinct  ideas  of  animals ; 
and  that  a  simple  cut  of  a  lion,  for  instance,  will  be  more  useful  in  giving 
an  impression  of  his  form  and  aspect,  than  a  whole  volume  of  verbal  de- 
scription. The  same  may  be  said  of  the  countenances  and  costumes  of 
various  nations  ;  of  the  peculiar  modes  of  building,  travelling,  worshipping, 
tc.  The  engravings,  therefore,  are  not  introduced  as  mere  embellishment* 
and  allurements  to  the  pupil,  but  as  an  efficient  and  essential  source  of  cor 
rect  information. 


18  Huntington  fy  Savage's  Publications. 

PETER    PARLEY'S    NEW    GEOGRAPHY    FOR 
BEGINNERS. 

Illustrated  with  18  beautifully  colored  Maps,  and  150  Engravings,  and  neatly 

bound  in  stiff  covers. 

It  were  needless  to  speak  of  the  felicity  of  style,  or  of  the  simple,  clear, 
and  practical  method  in  which  Peter  Parley  presents  to  the  young  the  sub- 
jects of  which  he  writes.  Notwithstanding  other  works  of  the  kind  have 
been  issued,  this  little  work,  more  full  and  accurate  than  any,  continues  to 
make  its  way  in  all  places  where  improvements  in  primary  education  are 
going  forward.  It  has  been  reprinted  in  England,  and  is  extensively  used 
throughout  that  country  and  Canada :  it  has  been  translated  into  French, 
and  is  much  used  in  France  ;  it  has  been  published  in  Greek,  and  introduced 
to  20,000  youth  of  that  nation.  It  has  also  been  translated  by  the  missionaries 
in  Persia,  and  introduced  into  their  schools,  and  has  been  more  recently  re- 
printed in  Sidney,  New  South  Wales.  This  foreign  use  is  evidence  of  the 
value  and  popularity  of  the  work  ;  yet  it  is  to  be  regretted  that  we  have  no 
copyright  law  to  give  authors  and  publishers  the  benefit  of  such  use. 


FAMILIAR  LECTURES  ON  BOTANY, 

PRACTICAL,  ELEMENTARY,  AND  PHYSIOLOGICAL: 

With  a  New  and  Full  Description  of  the  Plants  of  the  United  States,  and 

Cultivated  Exotics,  <fec.    For  the  Use  of  Seminaries,  Private 

Students,  and  Practical  Botanists. 

BY  MRS.  A.  H.  LINCOLN,— NOW  MRS.  PHELPS, 

PRINCIPAL   OF   THE   PATAPSCO   FEMALE   INSTITUTE   OF   MARYLAND. 

New  Edition,  revised  and  enlarged.    1  vol.  imperial  12mo. 

In  the  present  edition  of  this  work,  in  compliance  with  the  request  of  many 
teachers,  the  "  Descriptions  of  Genera  and  Species"  are  now  made  to  in- 
clude all  those  native  and  foreign  plants  which  the  pupil  will  be  likely  to 
meet  with  in  any  part  of  the  United  States.  The  author  has  been  anxious 
not  to  omit  Southern  and  Western  plants  of  any  interest,  and  large  additions 
under  this  head  have  been  made.  Should  teachers,  or  students,  observe 
such  omissions,  cpmmunications  on  the  subject,  made  to  the  author,  would 
be  gratefully  received.  The  author  has  now  thoroughly  revised  the  descrip- 
tions of  plants.  For  the  numerous  additions  made  she  is  indebted  to  several 
American  works,  especially  to  the  "  Botany  of  the  Northern  and  Middle 
States,"  by  Dr.  Beck ;  and  also  to  the  descriptions  of  Tony,  Bigelow,  and 
Elliot.  For  foreign  plants,  Eaton's  and  Wright's  Manual,  Withering's  Brit- 
ish Plants,  Loudon's  Encyclopedias,  and  some  other  works,  have  been  con- 
sulted. 

For  clearness,  simplicity,  and  philosophic  precision,  there  are  few  school- 
books  which  hold  a  more  pre-eminent  rank  than  Mrs.  Lincoln's  Botany  :  few 
certainly  have  a  wider  and  more  justly  deserved  popularity.  The  work  is 
divided  into  FOUR  PARTS— 

1st.  The  Analysis  of  Plants,  or  Lessons  in  Practical  Botany. 

2d.  The  Organs  of  Plants,  beginning  with  the  Root,  and  ascending  to  the 
Flower ;  or  what  is  termed  ELEMENTARY  BOTANY,  and  Vegetable  Phy- 
siology. 

3d.  The  different  Systems  of  Botany,  and  the  most  important  Natural  Fami- 
Se5 ;  the  most  interesting  genera  and  families  found  under  each  Class  and 
Order. 

4th.  The  progressive  appearance  of  Flowers  in  the  Season  of  Blooming  : 
the  Phenomena  produced  by  the  different  states  of  Light,  Atmosphere,  &c.  ; 
Geographical  Distribution. 


. 
Huntington  <f-  Savage's  Publications.  19 

History  of  Botanical  Science,  and  tne  Analogies  and  Contrasts  between 
organized  and  unorganized  matter  in  Nature. 

A  distinguished  and  experienced  teacher  in  natural  science  says  of  this 
work  :  —  "  Far  from  depreciating  other  works  on  this  subject,  I  think  my  re- 
mark will  not  be  invidious,  when  I  say,  that  I  think  it  far  better  adapted  to 
the  purposes  of  Elementary  Instruction  in  the  science  than  any  I  have  seen. 
I  am  much  delighted  with  the  easy  and  natural  method  by  which  it  intro- 
duces the  scholar  to  a  knowledge  of  the  first  principles  of  the  science,  and 
the  strict  philosophical  arrangement  it  employs  in  imparting  instruction. 
The  whole  work  has  the  impress  of  one  practically  acquainted  with  the  art 
of  teaching,  and  adds  another  proof  to  the  many  already  existing,  that  in- 
structors of  intelligence  are  generally  better  qualified  to  prepare  elementary 
works  than  those  who  have  never  had  any  experience  in  the  business  of 
1  caching." 


BY  THE  SAME  AUTHOR, 

DESIGNED  FOR  PRIMARY  AND  COMMON  SCHOOLS, 

BOTANY  FOR  BEGINNERS, 

AN    INTRODUCTION   TO    MRS.  LINCOLN'S    BOTANY. 

BY  MRS.  LINCOLN  PHELPS. 
1  vol.  18mo.  pp.  150. 

This  book  is  intended  chiefly  for  the  use  of  primary  schools  and  the 
younger  pupils  in  higher  schools  and  seminaries.  So  much  has,  of  late, 
been  urged  by  those  who  take  an  interest  in  the  subject  of  education,  in 
favor  of  introducing  the  Natural  Sciences  into  Common  Schools,  that  it  is 
to  be  hoped  that  the  time  is  not  far  distant  when  plants  and  minerals  will  be 
as  familiar  objects  of  study  in  our  district  school-house  as  the  spelling-book 
now  is.  Perhaps  some  parent  or  teacher  may  be  ready  to  inquire,  whether 
it  is  recommended  that  such  studies  shall  take  the  place  of  reading,  spelling, 
or  writing;  by  no  means;  but  every  teacher  knows  that  there  are  many 
listless  and  vacant  moments  when  even  the  most  active  of  his  pupils  seem 
tired  of  their  monotonous  pursuits  ;  habit  and  respect  for  their  teacher  may 
lead  them  to  sit  still  and  do  no  mischief  ;  but  it  is  not  difficult  to  perceive, 
by  the  heavy  eye  and  inanimate  countenance,  that  the  intellect  slumbers. 
These  are  the  moments  when  the  experienced  teacher  feels  the  need  of 
some  new  stimulant.  Instead  then  of  saying,  "John,  or  Lucy,  you  have 
been  sitting  idle  this  half  hour,  why  don't  you  mind  your  book  ?"  he  who 
understands  the  human  mind  is  aware  that  this  is  the  very  way  still  more  to 
disgust  his  pupil,  and  he  will  assuredly  be  ready  with  some  new  method  of 
awakening  attention.  Suppose,  then,  instead  of  a  rebuke  for  idleness,  the 
teacher  should  kindly  address  his  pupil  as  follows  :  "  You  have  been  so  long 
engaged  upon  a  certain  set  of  studies,  that  I  perceive  they  have  become  tire- 
some ;  I  think  of  introducing  a  new  study  into  the  school  ;  to-morrow  /  shall 
give  a  lecture  on  Botany  ;  you  may  therefore  bring  with  you  to-morrow  all  tne 
wild  lilies,  or  violets,  or  any  kind  of  common  wild  flower  that  you  can  find 
in  the  fields."  The  effect,  any  one  at  all  accustomed  to  the  care  of  children 
will  readily  understand.  But  it  may  be  said,  "  there  are  many  teachers  who 
are  not  capable  of  giving  a  lecture  upon  botany."  To  this  it  may  be  an- 
swered, that  every  teacher  who  is  in  any  degree  fit  to  be  such  can  use  the 
"  Botany  for  Beginners,"  even  though  they  never  heard  a  lecture  upon  the 
subject  of  botany  ;  it  will  teach  him  the  leading  principles,  and  he  can  ex- 
plain them  to  his  pupils  ;  this  will  be  lecturing  upon  Botany. 

Thousands  are  using  this  little  work,  and  give  the  strongest  testimony  in 
its  faror. 

The  successor  of  Miss  Beecher  in  the  Hartford  Female  Seminary  says  :— 
"  It  is  a  clear,  simple,  and  interesting  exhibition  of  the  principles  of  an  en 


•      .  i         • 

20  Huntington  fy  Savage's  Publications. 

tertaining  science,  adapted  to  the  comprehension  of  children,  for  whoa  -  is 
designed,  and  fully  capable  of  preparing  them  for  a  more  extended  trea-  v^€. 
It  is  particularly  recommended  to  the  instructors  of  our  common  school  -« 
an  interesting  employment  for  the  leisure  hours  of  their  scholars ;  an 
mothers,  as  an  assistant  to  them  in  the  great  work  of  storing  their  child*****  • 
winds  with  the  knowledge  of  the  works  of  their  Creator." 


PHELPS'  NATURAL  PHILOSOPHY, 

FOR    THE    USE    OF    SCHOOLS,    ACADEMIES,    AND    PRIVATE    STUDENTS. 

Illustrated  with  numerous  Engravings  from  original  designs. 

By  MRS.  LINCOLN  PHELPS. 

New  Edition.    1  vol.  12mo. 

PHELPS'  PHILOSOPHY  FOR  BEGINNERS. 

1  vol.  18mo. 

A  teacher  of  much  experience,  and  Principal  of  one  of  our  first  Academies 
says  of  these  works  :— 

"  The  subject  is  treated  in  a  manner  highly  scientific  :  the  engravings  de- 
signed for  illustrating  the  text  are  happily  chosen  and  executed  ;  and  a  de- 
gree of  freshness  pervades  the  whole  work  which  cannot  but  impart  life  and 
animation  to  the  student  of  its  pages.  But  more  than  all,  we  rejoice  to  see 
d  healthy  moral  feeling  diffusing  its  fragrance  over  the  whole." 

PHELPS'  CHEMISTRY. 

?*  *     ,  New  Edition.    1  vol.  12mo. 

PHELPS'  CHEMISTRY  FOR  BEGINNERS. 

1  vol.  18mo. 

Professor  Caswell,  of  Brown  University,  having  examined  some  of  the 
most  important  chapters  of  these  works,  says :— "  The  principles  of  the 
science  appear  to  be  stated  with  brevity  and  clearness,  and  are  happily  illus- 
trated by  familiar  and  well-selected  examples." 

UNIVERSITY  EDITION 
OF 

DR.  WEBSTER'S  DICTIONARY: 

Abridged  from  the  quarto  American  Dictionary,  with  Walker's  Key  to  the 
Pronunciation  of  Greek,  Latin,  and  Scripture  Proper  Names,  etc.  With 
a  Memoir  and  Bust  of  the  Author.  1  vol.  royal  duodecimo.  556  pages. 

WEBSTER'S  HIGH-SCHOOL  DICTIONARY. 

12mo.    360  pages. 

The  design  of  this  volume  is  to  furnish  a  vocabulary  of  the  more  common 
words,  which  constitute  the  body  of  our  language,  with  numerous  technical 
terms  in  the  Sciences  and  Arts,  and  many  words  and  phrases  from  other 
languages,- which  are  often  met  with  in  English  books,  with  a  brief  defini- 
tion of  each;  to  which  is  added  an  accented  vocabulary  of  CLASSICAL, 
SCRIPTURE,  and  MODERN  GEOGRAPHIC  NAMES.  The  Orthogra- 
phy and  Pronunciation  are  made  to  correspond  closely  with  those  editions 
of  the  work  of  the  author  recently  revised  under  the  editorship  of  Professor 
GOODEICH,  of  Yale  College. 


Huntington  fy  Savage's  Publications.  21 

WEBSTER'S  PRIMARY  SCHOOL  PRONOUNCING  DICTION-ART, 

With  Accented  Vocabularies  of  Classical,  Scripture,  and  Modern  Geogra- 
phical Proper  Names.  Square  IGmo.  New  edition,  revised  and  en- 
larged, corresponding  in  orthography  to  the  large  work  of  Dr.  Webster. 

This  work  embraces  about  ten  thousand  more  words  than  Walker's  School 
Dictionary,  and  is  especially  recommended  to  the  attention  of  teachers. 

Also— POCKET  EDITION,  in  several  styles  of  binding— cloth,  tuck,  gilt 
and  gilt  embossed. 

This  last  is  a  vocabulary  of  the  most  important  words  of  our  language, 
both  common  and  scientific,  with  a  concise,  primitive  definition  of  each 
word,  followed  by  the  derivations  of  the  same  word,— thus  presenting  the 
two  features  in  one,  of  a  defining  Dictionary,  and  one  of  the  Synonyms. 

The  following  Testimonial  is  subscribed  by  a  large  number  of  the  most 
distinguished  men  of  our  country  : 

"  The  subscribers  highly  appreciate  Dr.  Webster's  purpose  and  attempt  to 
improve  the  English  language,  by  rendering  its  orthography  more  simple, 
regular,  and  uniform,  and  by  removing  difficulties  arising  from  its  anomalies. 
It  is  very  desirable  that  one  standard  dictionary  should  be  used  by  the  nu- 
merous millions  of  people  who  are  to  inhabit  the  vast  extent  of  territory  be- 
longing to  the  United  States  ;  as  the  use  of  such  a  standard  may  prevent  the 
formation  of  dialects  in  states  remote  from  each  other,  and  impress  upon 
the  language  uniformity  and  stability.  It  is  desirable,  also,  that  the  acquisi- 
tion of  the  language  should  be  rendered  easy,  not  only  to  our  own  citizens, 
but  to  foreigners  who  wish  to  gain  access  to  the  rich  stores  of  science  which 
it  contains.  We  rejoice  that  the  American  Dictionary  bids  fair  to  become 
such  a  standard ;  and  we  sincerely  hope  that  the  author's  elementary  books 
for  primary  schools  and  academies,  will  commend  themselves  to  the  general 
use  of  our  fellow-citizens." 


THE  PRACTICAL  FRENCH  TEACHER. 

BY  NORMAN  PINNEY,  A.  M. 

The  leading  peculiarity  in  this  work  is.  that  it  exercises  the  student 
throughout  in  the  constant  practice  of  speaking.  The  preparation  of  every 
lesson  is  a  preparation  for  speaking  the  language,  and  every  lesson  is  an 
actual  conversation  in  it.  These  conversations,  too,  are  progressive  and 
systematic  ;  commencing  with  the  simplest  elements  of  the  language,  and 
advancing  by  an  easy  process,  to  the  more  difficult.  The  whole  has  been 
prepared  with  a  view  to  overcome  the  difficulties  which  an  American  meets 
in  acquiring  a  knowledge  of  that  so  necessary  part  of  a  finished  education. 


KEY  TO  PINNEY'S  PRACTICAL  FRENCH  TEACHER, 


THE  FIRST  BOOK  IN  FRENCH ;  or,  A  Practical  Introduction  to  the 
Reading,  Writing,  and  Speaking  of  the  French  Language.  By  NORMAN 
PINNEY,  A.  M. 

PICTORIAL  HISTORY  OF  THE  U.  STATES,  by  S.  G.  GOODRICH- 
PICTORIAL  HISTORY  OF  FRANCE,  by  S.  G.  GOODRICH. 
PICTORIAL  HISTORY  OF  ENGLAND,  by  S.  G.  GOODRICH. 

PICTORIAL  HISTORY  OF  ROME,  by  s.  G.  GOODRICH. 

PICTORIAL  HISTORY  OF  GREECE,  by  S.  G.  GOODRICH. 

The  above  series  of  histories,  formerly  published  by  Messrs.  Sorin  &  Ball, 
of  Philadelphia,  js  very  extensively  introduced  into  both  private  and  public 
institutions  throuehout  the  Union. 


22  Huntington  fy  Savage's  Publications. 

ENGINEER'S    &    MECHANIC'S    COMPANION; 

Comprising  Mensuration  of  Superfices  and  Solids ;  tables  of  Squares  and 

Cubes ;  Square  and  Cube  Roots  ;  Circumference  and  Areas  of  Circles . 

the  Mechanical  Powers  ;  of  Steam  and  Steam  Engines  ; 

United  States  Weights  and  Measures,  &c. 

BY  J.  M.  SCRIBNER,  A.  M. 
1  vol.  18mo.,  240  pages.    Morocco,  gilt,  with  tucks. 

This  work  is  highly  recommended  by  several  distinguished  civil  engineers 
and  machinists ;  and,  as  a  Manual  for  practical  mechanics,  is  a  work  of 
great  value.  Besides  the  general  topics  already  enumerated,  it  contains  a 
vast  amount  of  valuable  matter,  in  relation  to  Centres  of  Gravity ;  Gravita- 
tion of  Bodies  ;  Pendulums ;  Specific  Gravity  of  Bodies ;  Strength,  Weight, 
and  Crush  of  Materials ;  Water  Wheels  ,  Hydrostatics  ;  Hydraulics ;  Statics  . 
Centres  of  Percussion  and  Gyration  ;  Friction  ;  Heat ;  Tables  of  Weights  of 
Mentals  ;  Pipes,  Scantlings  ;  Interest ;  &.c.  &,c. 

THE   ENGINEER'S,  CONTRACTOR'S,  AND  SURVEYOR'S 

POCKET  TABLE-BOOK, 

BY    J.    M.    SCRIBNER,    A.M. 
264  pages,  24mo.    Tuck  binding,  with  gilt  edge. 

The  above  work  comprises  Logarithms  of  Numbers,  Logarithmic  Sines 
and  Tangents,  Natural  Sines  and  Natural  Tangents  ;  the  Traverse  Table,  aud 
a  full  and  extensive  set  of  tables,  exhibiting  at  one  view  the  number  of  Cu- 
bic Yards  contained  in  any  embankment  or  cutting,  and  for  any  base  or  slope 
of  sides  usual  in  practice.  Besides  these  essential  tables,  the  work  comprises 
50  pages  more  of  Mensuration,  Tables,  Weights  of  Iron,  Strength  of  Mate- 
rials, Formulas,  Diagrams,  etc.,  for  laying  out  Railroads,  Canals,  and 
Curves  ;  much  of  which  has  never  before  been  offered  to  the  public,  and  all 
indispensable  to  the  engineer.  This  book  will  prove  a  great  saving  of  time, 
and  will  enable  the  new  beginner  to  furnish  results  as  accurately  (and  will) 
much  greater  rapidity)  as  the  most  experienced  in  the  profession,  without  its 
aid.  The  tables  of  logarithms,  etc.,  have  been  carefully  corrected  and  com- 
pared with  different  editions  of  the  same  tables  ;  and  all  the  tables  througli- 
out  the  book  have  been  read  carefully  by  proofs  four  times  ;  hence  the  most 
implicit  confidence  may  be  placed  in  their  correctness. 

KAME'S    ELEMENTS    OF    CRITICISM. 

1  vol.  8vo. 
$5"  The  only  edition  which  received  the  latest  revision/pfc^he  Auther. 

PRESTON'S    BOOK-KEEPING,       *^   - 

DOUBLE  AND  SINGLE  ENTRY. 

PRESTON'S    INTEREST   TABLES; 

6  per  cent.— Large  and  Abridged.    7  per  cent.— Large  and  Abridged. 


Any  valuable  Books  to  be  had  in  New  York,  win  be  fur- 
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